Ash Barty stunned the sporting world on Wednesday by announcing her retirement from tennis, bowing out as the top-ranked player in the women's game.

The popular 25-year-old has not featured since winning her home grand slam at the Australian Open in January, becoming the first female Aussie singles champion of the tournament since Chris O'Neil in 1978.

Announcing the news on her Instagram page, Barty cited achieving a lifelong goal of winning Wimbledon last year as a primary factor behind her decision as well as being "spent physically".

But Barty is by no means the first sporting hero to retire at the top of their game. Below we take a look at some other examples of those who have exited as champions.

ALAIN PROST

The 1993 Formula One season was largely dominated by one man – Williams driver Alain Prost. The Frenchman had to battle hard with the iconic Ayrton Senna at the start of the campaign, with them each taking three wins from the first six races of the season. However, a run of four straight victories for Prost were followed by a string of retirements for Senna, ensuring a fourth world title that provided the ideal ending to a glittering career.

ALEX FERGUSON

One of the most successful managers in world football, Alex Ferguson began a 27-year stint at Manchester United after an excellent spell at Aberdeen. The Scot won 28 major trophies at Old Trafford, including 13 Premier League titles, five FA Cups and two Champions Leagues. His final trophy came with top-flight glory in 2012-13, and 17 days later he brought the curtain down.

PEYTON MANNING

Considered one of the greatest quarterbacks of all time, Peyton Manning won his first Super Bowl with the Indianapolis Colts in 2007 and, after an injury-blighted season that raised doubts about his ability aged 39, he added a second with the Denver Broncos in 2016, bowing out on the ultimate high.

RICHIE MCCAW, DAN CARTER

New Zealand became the first nation to successfully defend the Rugby World Cup trophy by beating Australia 34-17 in the final at Twickenham in 2015, adding to their success on home soil four years prior. It proved the end of the line for captain Richie McCaw, who was at the time the most capped player in rugby union with 148 appearances for the All Blacks, as well as mercurial fly-half Dan Carter. Ma'a Nonu, Conrad Smith and Kevin Mealamu were also among an influential contingent that opted to end their international careers.

PETE SAMPRAS

In defeating Andre Agassi in the final of the 2002 US Open, the same opponent he overcame to win his first grand slam 12 years prior, Pete Sampras secured his place among the greats in men's tennis. It was a then-record 14th major singles title for a male player for the American, a milestone that has since been surpassed by Roger Federer, Rafael Nadal and Novak Djokovic, but he did not compete again and announced his retirement almost one year later.

PHILIPP LAHM, MIROSLAV KLOSE

At 31 you still have a number of years ahead of you in football. However, after lifting the World Cup trophy with Germany in 2014, Philipp Lahm decided to call time on his international career and focus on club football with Bayern Munich. The versatile full-back made 113 appearances for his country and was joined by fellow centurions Per Mertesacker and Miroslav Klose – whose tally of 71 international strikes is a German record – in switching focus to domestic matters.

MARION BARTOLI

A first grand slam at Wimbledon in 2013 appeared to be the breakthrough moment for a 28-year-old Marion Bartoli, but reality proved very different. The Frenchwoman defeated Sabine Lisicki – who had overcome pre-tournament favourites Serena Williams and Agnieszka Radwanska – in the All England Club final, but announced her retirement during the Western and Southern Open just 40 days later due to persistent injuries. She attempted a comeback in 2018 but continued setbacks and injuries curtailed those plans.

NICO ROSBERG

Nico Rosberg had engaged in several intense battles with Lewis Hamilton before finally getting the better of his Mercedes team-mate to become Formula One world champion in the 2016 season. Still only 31, Rosberg had potentially several more years in F1 but the German instead opted to depart having reached the pinnacle of his sport.

Rafael Nadal, the 21-time grand slam winner, says the recently announced introduction of final-set tie-breaks across all grand slams will make the biggest impact at Wimbledon, rather than the French Open.

Tennis' Grand Slam Board announced this week that first-to-10 tie-breaks will be trialled across all grand slams with immediate effect, as a means of providing "greater consistency" to matches which go the distance.

Previously, each grand slam was free to adopt its own rules for deciding longer matches, with the Australian Open the only one to use first-to-10 tie-breaks at 6-6 in a deciding set.

Wimbledon, for example, used a first-to-seven tie-break to decide final sets which reached 12-12.

Speaking after dispatching Reilly Opelka in straight sets at the Indian Wells Masters, Nadal, who will look to add to his Australian Open triumph in the year's other three majors, explained he was not for or against the changes.

The 35-year-old also, however, predicted the alterations would have a bigger impact at Wimbledon than at the French Open, which he could win for a 14th time at Roland Garros in May.

"I don't care much, honestly!" said Nadal. "I am not in favour or not against, that's what they decided, and happy with it or not, I don't think I'm going to make a big difference.

"But I read that every [tournament] is going to have the same, and in some ways that's positive.

"I don't think at Roland Garros it will make a big impact. In my opinion the biggest impact is going to be at Wimbledon, [where] sometimes it's so difficult to break serve, so the matches become very long.

"I don't feel that for Roland Garros it will change a lot. Okay, [without the changes] it can be a few more games, but I don't think at Roland Garros you're normally going to go to 22-20. At Wimbledon, that can happen."

The longest men's singles match played at a grand slam, judged by the number of games played, came at Wimbledon in 2010, when John Isner beat Nicolas Mahut 6-4 3-6 6-7 (7-9) 7-6 (7-3) 70-68.

By contrast, the longest men's singles match in French Open history saw Fabrice Santoro beat fellow Frenchman Arnaud Clement 6-4 6-3 6-7 (5-7) 3-6 16-14, in 2004. 

After defeating Opelka in his round-of-16 tie at Indian Wells, Nadal will now face Australia's Nick Kyrgios for a place in the semi-finals.

Earlier in the week, the Spaniard became the first-ever player to reach 400 wins at Masters 1000 tournaments by beating Dan Evans in the last 32. 

The Grand Slam Board has announced that first-to-10 tie-breaks will conclude the final sets of all four majors with immediate effect.

Starting with May's French Open, the decision is being adopted on a trial basis with the aim of providing "greater consistency" to the rules when matches go the distance.

Prior to Wednesday's announcement, the French Open, Australian Open, US Open and Wimbledon each had their own rules when games went to a deciding tie-break.

The Australian Open is the only grand slam to already employ the first-to-10 rule at 6-6.

Wimbledon previously played first-to-seven at 12-12, while the US Open played a first-to-seven at 6-6.

There has not previously been a deciding tie-break at Roland-Garros, with all matches continuing until a player secured a two-game lead in the decider.

A statement released on behalf of Grand Slam Board members Jayne Hrdlicka, Gilles Moretton, Ian Hewitt and Mike McNulty confirmed the changes.

It read: "The Grand Slam Board's decision is based on a strong desire to create greater consistency in the rules of the game at the Grand Slams, and thus enhance the experience for the players and fans alike.

"This trial, which has been approved by the rules of the tennis committee governed by the ITF, will apply to all Grand Slams across qualifying, men's singles and doubles, women's singles and doubles, wheelchair and junior events in singles, and will commence at the 2022 edition of Roland-Garros."

The rule change will be reviewed after a full Grand Slam year and will remain in place should it be deemed a success.

The tweaks to the current format will ensure no repeat of John Isner's marathon battle with Nicolas Mahut at Wimbledon in 2010, which the American edged 70-68 in the final set of their first-round match.

Daniil Medvedev and fellow Russian tennis stars could be banned from playing at Wimbledon unless they denounce president Vladimir Putin.

That was confirmed by UK sports minister Nigel Huddleston on Tuesday, as he told a parliamentary committee there were concerns about Russian representation in sport.

With Russia's military invasion of Ukraine ongoing, Huddleston warned it would not be appropriate for anyone to be seen to be flying the flag for their homeland, or showing any support for Putin's regime.

Speaking at a Digital, Culture, Media and Sport Committee session, Huddleston was asked about Wimbledon and Medvedev, the current men's world number one player and reigning US Open champion.

Huddleston said: "We are looking and talking to various sports about this and what the response and requirements should be there. Absolutely, nobody flying the flag for Russia should be allowed or enabled."

He added: "We need some potential assurance that they are not supporters of Vladimir Putin and we are considering what requirements we may need to get some assurances along those lines.

"In short, would I be comfortable with a Russian athlete flying the Russian flag? No."

Asked about the All England Club, which hosts Wimbledon, Huddleston said: "We are in discussions."

Russia has four players in the men's top 30, and three in the women's top 30.

They are playing under neutral flags at present, after the ATP and WTA tours decided Russian and Belarusian players should not be permitted to represent those nations while conflict continues in Ukraine.

Wimbledon runs from June 27 to July 10 this year, with a week of qualifying preceding the tournament.

Demanding each player from Russia directly comes out against president Putin would be going a step beyond what is currently required.

Huddleston said: "We are looking at this very issue about what we do with individuals, and we are thinking about the implications of it, because I don't think people would accept people very clearly flying the Russian flag, in particular if there is any support and recognition for Putin and his regime."

Speaking last week at Indian Wells, Medvedev spoke about being allowed to continue to play on the tour.

"It's definitely not for me to decide. I follow the rules. I cannot do anything else," he said. "Right now the rule is that we can under our neutral flag.

"I want to play my favourite sport. Until I have the chance to do it, I'm going to be there to try to play for the fans, play for other people, for myself also of course.

"Also I think tennis is a very individual sport, so far what we are seeing [being sanctioned] are more national teams or some team sports. Let's see how the situation evolves."

The ATP, WTA, International Tennis Federation (ITF) and the four grand slam organisers have announced the Tennis Plays for Peace campaign.

Along with the campaign, which will include efforts on social media and at tournaments, each of the seven organisations has pledged to donate $100,000 to humanitarian relief efforts in Ukraine.

Russia invaded the country on February 24 and the conflict is still ongoing. Well over one million refugees are estimated to have fled to neighbouring countries in Europe.

A joint statement from tennis' governing bodies on Tuesday explained that the campaign is not just about donations.

"The seven bodies will also signal support via their social and digital platforms by prominently featuring the Ukraine ribbon icon, with everyone in the tennis ecosystem encouraged to use the hashtag #TennisPlaysforPeace," it read.

"In addition, physical ribbons will be distributed for ATP and WTA players to wear at the upcoming BNP Paribas Open tournament in Indian Wells."

Last week, the ITF banned Russian and Belarusian teams from competing at the Davis Cup or the Billie Jean King Cup. Russia are the holders of each title.

The ATP and WTA, meanwhile, allowed Russian and Belarusian athletes to carry on competing, but only under neutral banners.

That includes ATP world number one Daniil Medvedev and WTA world number three Aryna Sabalenka.

Roger Federer says he hopes to return to action by the end of the summer, with his recovery from knee surgery likely to rule the 20-time grand slam winner out of Wimbledon.

The 40-year-old underwent surgery on his right knee for the third time last August, and has missed five of the last seven grand slams.

Federer made the quarter-finals at Wimbledon last year, but coach Severin Luthi recently said that he "can't imagine" the eight-time Wimbledon winner featuring in London this summer.

Federer has now provided an update on his recovery to Swiss broadcaster SRF, saying that the end of summer or start of autumn is a realistic target for his return, which could mean he is back for the US Open that starts on August 29.

However, he feels "positive" about his return to the court whenever that comes.

"It will certainly be a while," Federer said. "The end of the summer, early autumn, [that's] where I'm aiming for a comeback.

"It's [the knee] fine. Much better. Obviously, I was on crutches for two months, so you have to start from the bottom.

"It [the surgery] was certainly the right thing to do, the knee wasn't right after Wimbledon [last year], so it couldn't go on.

"Currently I'm in three parts. First, the whole rehab, getting back on your feet at the beginning. Then afterwards, learning to walk and building up the whole thing.

"It's only now where I'm at the phase where I can start thinking about my comeback. I had a very good MRI a few weeks ago, which makes me feel very positive."

Federer's tally of 20 career Grand Slam titles was surpassed by Rafael Nadal in January's Australian Open, and the duo are set, fitness permitting, to team up to represent Europe in the Laver Cup, which takes place in September.

The timeline for Federer's recovery also means that he will miss the second slam of 2022, May's French Open at Rolland Garros.

Rafael Nadal would "welcome" seeing Novak Djokovic play at future grand slam tournaments if he is granted permission to do so unvaccinated against COVID-19.

World number one Djokovic has courted controversy for his views on being jabbed and was last month deported from Australia on the eve of the Australian Open.

Djokovic has confirmed he is willing to miss future slams after stating he was prioritising his right to choose what to put into his body above his sporting ambitions.

In Djokovic's absence, Nadal became Australian Open champion and now has 21 titles – the most for a male player.

Nadal believes that any further omissions from Djokovic would only be harmful to the Serbian's chances of history not the slams themselves, but he would have no issue with his rival playing in the sport's biggest tournaments.

Speaking ahead of his return to the ATP Tour in Acapulco, Nadal said: "It will affect Novak's [grand slam] history if he can't play.

"It will affect him, not the grand slams themselves. Whoever wins the most slams – it will be what it will be. Everyone takes their own decisions and must live with them.

"In that sense, hopefully the pandemic subsides and we stop having so many deaths around the world and this horror ends, and we can return to normality – not for Novak but for the world in general.

"There are many people that have suffered, but if Novak can play the grand slams unvaccinated, then he is welcome."

Nadal defeated Daniil Medvedev in an epic Melbourne showpiece to become the first man to 21 slams, but he says the achievement has not changed his life.

"Absolutely nothing has changed having 21 slams, I won't lie to you," he added.

"From 20 to 21 there is not a very large difference. Life goes on exactly the same. The only thing that has changed is that now I play tennis, which a few months ago I couldn't.

"I am very happy for everything that happened in Australia, it was very unexpected, especially before the tournament started. In my life, nothing has changed. No title is going to change what is important in my life, which are other things.

"Already, at 35 years old, I have a lot of experiences behind me, of successes and bad moments and these sensations already help me to live in a more calm and different way."

Novak Djokovic has said missing grand slams including the French Open and Wimbledon will be "the price I am willing to pay" for resisting the COVID-19 vaccine.

Last month, the world number one and 20-time grand slam winner was deported from Australia on the eve of the Australian Open after his entry visa to the country was cancelled.

That stemmed from Djokovic refusing to join the overwhelming majority of fellow tennis stars in being vaccinated against coronavirus, and amid controversy over how he handled getting the virus himself in December.

In a new interview with the BBC, Djokovic said he was prioritising his right to choose what to put into his body above his sporting ambitions.

The 34-year-old Serbian declared his stance is likely to keep him sidelined for "most of the tournaments" at present.

Djokovic is set to make his return to the court at the Dubai Duty Free Tennis Championships later this month, with vaccination not a requirement. He has been included on the entry list for next month's Indian Wells Open, but that is a tournament he may have to sit out.

He confirmed in the BBC interview that he has still yet to be vaccinated, though did not entirely rule out the prospect in the future.

"I have not," he said. "I understand and support fully the freedom to choose whether you want to get vaccinated or not."

Prior to entering Australia, where he was obliged to confirm his status, it was only widely assumed that Djokovic had not been inoculated.

Now he is keen to "speak up ... and justify certain things", adding: "So I was never against vaccination. I understand that globally everyone is trying to put a big effort into handling this virus and seeing hopefully an end soon to this virus.

"And vaccinations are probably the biggest effort that was made on behalf of the planet. I fully respect that, but I've always represented and always supported the freedom to choose what you put into your body. For me that is essential. It's really the principle of understanding what is right and what is wrong for you.

"And me, as an elite professional athlete, I've always carefully reviewed and assessed everything that comes in, from the supplements, food, the water that I drink or sports drinks. Anything really that comes into my body as a fuel.

"Based on all the information that I got, I decided not to take the vaccine as of today. I keep my mind open because we are all trying to find collectively a best possible solution to end COVID. Nobody really wants to be in this kind of situation that we've been in collectively for two years."

Djokovic is the reigning French Open and Wimbledon champion and, after Rafael Nadal's Australian Open triumph, he has been bumped down to joint second on the all-time men's grand slam list. Missing majors at this stage of his career could be a crushing blow to Djokovic's hopes of finishing top of that pile.

"I'm part of a very global sport that is played every single week in a different location, so I understand the consequences of my decision, and one of the consequences of my decision was not going to Australia, and I was prepared not to go," Djokovic said.

"I understand that not being vaccinated today I am unable to travel to most of the tournaments at the moment. That is the price I am willing to pay."

He looked to disassociate himself from the anti-vax community by saying he had "never said I am part of that movement" and declaring that was a "wrong conclusion" to draw.

At the same time, Djokovic concurred when asked if he was willing to sacrifice the chance to be seen as the greatest player of all time, and to travel to Roland Garros and the All England Club this year.

"Because the principles of decision-making on my body are more important than any title or anything else. I'm trying to be in tune with my body as much as I possibly can," Djokovic said.

"I say that everyone has a right to choose to act or say whatever they feel is appropriate for them."

Andy Murray has decided to skip the entire clay court season, including the French Open, as he feels the surface aggravated "issues" in the past.

Former world number one Murray has endured a torrid time with injuries in the past few years, but he has featured more regularly since the second half of last season.

While he only made it as far as the second round at last month's Australian Open, his preparation for the year's opening grand slam saw him reach a first final on the ATP Tour since October 2019.

He lost to Aslan Karatsev in the decider of the Sydney Classic, going down 6-3 6-3, but the Scot's run to the final provided evidence he still has plenty to offer.

Murray will not be playing in the next grand slam, though.

The eyes of the tennis world will be on Roland Garros in late May and early June, but Murray is opting to miss that and every other event on clay for fear of worsening his condition, with Wimbledon scheduled to begin on June 27.

"Right now, I am not planning on playing through the clay," the three-time grand slam winner said.

"The past couple of years, the clay has made issues worse; last year I had some issues at the beginning of the year, the clay didn't help, so I've spoken to my team about that and this year while I feel good and healthy, I don't want to take that risk.

"It's not that I wouldn't potentially play on clay in the future. Last year I almost missed Wimbledon, was close to not playing the grass season. I'm not planning on playing the clay. I will still try to compete a bit during that period, I won't do nothing, that's my plan just now.

"I had a busy end of last year and the next couple of months I won't take any risks and hopefully get a good build up to the grass season."

Murray parted ways with long-term coach Jamie Delgado in December and then decided against making Jan de Witt a permanent member of his team following a trial period leading up to and through the Australian Open.

The 34-year-old is now once again working with Dani Vallverdu, Stan Wawrinka's coach, having teamed up with him between 2010 and 2014.

But Murray accepts the situation is far from ideal, with Vallverdu only available while Wawrinka continues his rehabilitation from a foot injury that has kept him out since March last year.

"It's not been easy to find someone," Murray added.

"Obviously, Stan Wawrinka has been rehabbing for quite a long time and is hopefully coming back to the tour, but he agreed for Dani to come and work with me for a few weeks over the next month or so, which is great for me in the short term, but still trying to find a longer-term solution.

"It's not that straightforward, I'm not as in demand as a few years ago. Ultimately, I want it to be the right person. I'm aware there's no perfect setup, but medium, longer term I want some stability and will try and get that in the next few weeks."

Roger Federer still has the drive to return to the ATP Tour but is yet to run and is still months away in his recovery from a third knee operation.

The 40-year-old 20-time grand slam winner missed last month's Australian Open after a knee operation in August.

Federer has not played since a quarter-final loss to Hubert Hurkacz at Wimbledon last year and previously said he would be "incredibly surprised" if he was fit to play at the event in 2022.

"It's a very important next few months ahead of me," Federer said at a sponsor's event on Wednesday. "I'll know a whole lot more in April what my body is going to be like.

"Up until now I was not able to run yet and do the heavy workload. I hope that starts in the next couple of weeks and then we'll see how my body reacts.

"For now, the drive is there. I'm really motivated to do my work and what I'm allowed to do. I'd love to do way more, but the doctors are holding me back a bit."

The eight-time Wimbledon champion elaborated on his recovery, revealing he hopes to put weight on his knee again in the coming weeks.

"I can still not run. But I'm working daily in the gym," Federer said. "I really hope that I can put weight on my knee again in two to three weeks. Then we'll see how the body reacts so we can hit the ball again in April or May."

He added: "Of course I wish that everything could go quicker. But the doctors don't want me to overdo everything."

Spanish tennis great Manolo Santana, a four-time grand slam winner, has died at the age of 83.

Santana won the US Open, Wimbledon and the French Open twice during the 1960s, during which time he spent a period as world number one.

He also won the men's singles tennis tournament at the 1968 Olympics, though it was not recognised as a medal event at the time, while also winning the French Open men's doubles in 1963 and the Davis Cup with Spain on three occasions.

Santana retired in 1977 and in more recent times was regularly seen watching countryman Nadal – the only Spaniard to have won more grand slam titles – from the stands.

Nadal led the tributes to Santana on Saturday with an emotional post on social media.

"I have just received the terrible news of the death of our great Manolo Santana," he wrote on his official Instagram account.

"As I have said many times in the past: thank you very much for what you did for our country and for leading the way for so many. 

"You have always been a reference, a friend and a person close to everyone.

"We will miss you Manolo; you will always be unique and special. Greetings to your family and a lot of strength at this time. We will never forget you."

Ash Barty has announced her engagement to Liverpool fan and golfer Garry Kissick, capping a memorable year in style.

Barty added another sparkler to her collection when she revealed an engagement ring on Tuesday, having already landed the glistening Wimbledon trophy and an Olympic medal in the 2021 season.

She posted a picture of herself and Kissick on Instagram, showing off her ring and captioning the shot "Future Husband".

Kissick is a trainee professional at Brookwater Golf Club, a venue close to Brisbane, and is often seen in a Liverpool Football Club shirt, as was the case with the engagement picture.

He and Barty have visited Liverpool's home ground of Anfield together.

Speaking about having the likes of Kissick and coach Craig Tyzzer with her on the road, Barty said during her run to the Wimbledon title in July: "It's nice to be able to share some of these awesome moments with those that put so much time and energy into my career and allow me, encourage me, help me kind of work and figure out a plan and a way that they try and achieve our dreams. I think being able to share that with them is really special."

Barty won a bronze in mixed doubles at Tokyo 2020 alongside long-time friend John Peers, describing that achievement as "a dream come true".

She also won the Yarra Valley Classic, the Stuttgart Open, and WTA 1000 titles at Miami and Cincinnati before calling time on her season after a third-round exit from the US Open, where she lost to Shelby Rogers.

Barty finished the season as world number one for a third successive year, despite her recent inactivity.

She said a major triumph in her homeland was a priority for 2022, saying: "My focus is now on the Australian summer and doing everything I can to win the Australian Open. I can't wait to play at home again."

Roger Federer has confirmed he will not participate at the Australian Open and said he would be "extremely surprised" if he is fit enough to play at Wimbledon.

The 20-time grand slam winner has played just 13 matches in 2021 as he recovers from a third knee surgery in the space of 18 months, with Federer's last appearance a disappointing straight-sets loss to Hubert Hurkacz in the quarter-finals at SW19 in July.

The Swiss great has now officially confirmed he will not be at Melbourne Park for the first grand slam of 2022, while it remains touch-and-go whether Federer will be back at Wimbledon this year.

"At the moment, I expect to be able to return in the summer of 2022," he told Tribune de Geneve having confirmed playing in Australia is out of the question. 

"The next four or five months are crucial. In the spring, I will already see things much more clearly. The truth is that I would be incredibly surprised if I were to play again at Wimbledon [in 2022]."

"When you get right down to it, it doesn't make much difference whether I return in 2022 or not until 2023, at 40 or 41. It doesn't matter. The question is rather will I manage to torture myself again day after day for my comeback?

"My heart says 'yes' today. So, I'm taking things step by step. I have experienced similar challenges many times in my career sometimes without the public being aware of it. Even though I know that the end is near, I want to try to play some big matches again. It won't be easy but I will try."

Now aged 40, Federer's latest injury setback led to suggestions he could call time on his glittering career, though his coach Ivan Ljubicic this week said he was not contemplating such a decision.

Federer accepts he may never play in a grand slam final again and is at peace with that fact, but still "believes in these miracles" as he aims to once again compete among the elite level.

"If I do my rehabilitation intensively, there is a chance that I will get back to a high level," he added. 

"If I do strength training, go on the bike, swim, do balance exercises, work on my upper body, then I believe in it.

"Will I return to the Tour for a smaller round or for something bigger? Nobody knows, neither the doctors nor me. But I'm fighting for it. To be clear, my world will not collapse if I never play another grand slam final.

"But it is my ultimate dream to return once again. And in fact, I still believe in it. I believe in these kinds of miracles. I have already experienced them. 

"Sports history sometimes writes such miracles. I am realistic – it would be a great miracle but there are miracles in sport."

Roger Federer's body has been saying no for the past two years, but Pat Cash is hopeful the 39-year-old will return for another run on the ATP Tour.

After suffering a setback to his longstanding knee injury during Wimbledon, the 20-time grand slam champion has this week withdrawn from the Tokyo Olympics.

Despite being without much match practice – playing just four tournaments before Wimbledon after coming back from two knee surgeries - Federer was able to make the quarter-finals at All England Club.

However, he suffered a demoralising loss to Hubert Hurkacz in straight sets in the last eight that promoted a fresh round of speculation over his future in the game.

Cash, who won Wimbledon in 1987, hopes Federer will be back despite his recent injury woe.

He told Stats Perform: "First of all, let's hope that Roger Federer will keep going. 

"I think he can, I think he just needs more matches and probably needs to make sure that he's able to last. 

"But your body starts saying no at some stage and it's been saying that for a couple of years now for him." 

Wimbledon winner Novak Djokovic is now level with Rafael Nadal and Federer on 20 slams.

Cash believes judging the Swiss star purely on grand slam titles is not a fair measure of his brilliance, pointing instead to his astonishing record totals of 58 major quarter-final berths and 46 semis.

"He has been the most consistent player that I think we've ever seen," Cash said. "He may not end up with as many grand slams but his consistency is just outrageous.

"All the other players have lost early in grand slams, the Djokovics, the [Andy] Murrays, then the Nadals had lost early in grand slams, Roger just doesn't do it.

"Of all the titles that he's won, I think for me, his most impressive record is how many semi-finals or quarter-finals in grand slams in a row that he got to. It was something ridiculous for 10 or 11 years.

"He never failed at any grand slams and that is just absolutely mind blowing."

However long he tries to play on, Cash insists nothing can sour the memories of an extraordinary career from Federer.

Cash added: "Obviously, he raised the bar as far as the standard of tennis has gone. 

"The other players really had to catch up. Novak admitted it, he said, 'Without Roger there, leading the way, I wouldn't have been as good a player as I could have been'. 

"That's the gold standard of Roger Federer over his career and I'm not sure anybody will be as consistent as him in tennis history. 

"He's just phenomenal the way he plays, and we all of course enjoy the style, his movement. And he's a class act off the court as well."

Federer's status for the US Open, which begins on August 30, is unclear, with Djokovic looking to take the outright lead for major titles and achieve a historic calendar year Grand Slam.

Novak Djokovic will never have a better opportunity to achieve a historic calendar Grand Slam, which former Wimbledon champion Pat Cash says he should prioritise at all costs.

The Serbian won a sixth Wimbledon crown on Sunday, defeating Matteo Berrettini in four sets to achieve a final victory that moved him on to 20 grand slam titles.

With Australian Open and French Open successes also already achieved, glory at the US Open would see Djokovic become only the second men's player in Open Era history to win all four majors in the same year.

Cash thinks the stars have aligned for Djokovic, with issues for his main rivals leaving the 34-year-old primed to achieve the famous feat in 2021.

"The impossible dream really is there," Cash said to Stats Perform.

"For Novak this year it is a great opportunity for him to grab a bunch of grand slams and grab all the titles. 

"Certainly Wimbledon – without disrespecting the other players – was one of the weaker men's side draws that I've seen in many, many years. 

"And that's because we've got two of the big stars coming back from injuries – Andy Murray and Roger Federer – who played well but weren't at the peak of their career.

"The younger players are coming through but they're not quite there yet and Novak is just sitting on top of that mountain as the King of the Castle.

"His performance was exceptional at Wimbledon, there's no doubts about it. 

"The slightly younger players are coming through – Berrettini obviously in the final really pushed him to just about the limit.

"Stefanos Tsitsipas in the French Open final up two sets to love. So, these guys are close, very close, and it won't be long before they catch up with Novak and the others. 

"Obviously Rafa [Nadal] was out of this Wimbledon as well – I don't really think he's a serious threat on the grass anymore but he's still a great competitor. 

"So these guys are catching up, Rafa is still there, maybe Murray will come back and Federer will come back and be in better shape in the next year – but this is the year that Novak can really grab." 

Djokovic admitted this week he is still "50/50" over whether he will take part in the upcoming Tokyo Olympics due to coronavirus countermeasures in the Japanese capital. 

Federer withdrew from the tournament on Tuesday and Cash insists Tokyo will not be the priority over glory in New York for Djokovic.

Cash added: "It's the Olympics, okay – maybe he wants to do that, but certainly his goal is now to try and win all four grand slams in the calendar year.

"He has done four in a row, but he hasn't done them in the same year, which is very, very tough to do. 

"There is a reason why I think one person has done it in [men's] professional tennis – Rod Laver and it was in 1969, so it's not easy to do. 

"But I really do think it's in his sights and that has got to be his priority. 

"It's absolutely the absolute peak of our sport to win all four grand slams in one year." 

With Djokovic now level with Federer and Nadal on 20 majors, Cash would not be surprised to see him build a big lead.

He added: "Look, it's very hard to say. We have all been proven wrong by the numbers. 

"Though most of us thought that Rafa and Novak would get pretty close to Federer, we didn't really think they'd get there and beyond. 

"I think Novak is likely to win another couple, but you know, it takes us one little injury [to derail him] so it is very hard to say.

"John McEnroe said 25 or so [for Djokovic] and that could be well within his reach at the moment. 

"He's improving and that's frightening to think. He's won 19 grand slams before Wimbledon, and all of a sudden we've seen this guy come to the net, volley, add another string to his bow to become a better player. 

"Yeah, age 34 and he is improving – that's pretty frightening."