Nick Kyrgios has dragged tennis into the gutter with his Wimbledon antics, according to Pat Cash.

According to Kyrgios' compatriot Cash, the Australian has taken the sport "to the lowest level" with his on-court behaviour in the first week of the tournament.

The 27-year-old beat fourth seed Stefanos Tsitsipas 6-7 (2-7) 6-4 6-3 7-6 (9-7) in an enthralling round-three tie on Saturday.

Tsitsipas accused his opponent of "constant bullying" after the ill-tempered clash, which was followed by a riposte as Kyrgios said the beaten Greek was "soft" and denied being a bully.

Kyrgios frustrated Tsitsipas by calling for him to be defaulted after the world number five narrowly missed a spectator when firing a ball into the crowd at the end of the second set.

The umpire was then labelled a "disgrace" during an extraordinary Kyrgios outburst, and his behaviour seemed to get under the skin of Tsitsipas, who was deducted a point for sending another ball towards the spectators before appearing to hit a couple of shots directly at his opponent's body.

Kyrgios has been a repeated critic of umpires and line judges, often appearing to show contempt to authority figures, and Cash – Wimbledon champion in 1987 – has had enough, calling out his countryman's conduct.

Speaking on BBC Radio 5 Live, Cash said: "It was absolute mayhem. He's brought tennis to the lowest level I can see, as far as gamesmanship, cheating, manipulation, abuse, aggressive behaviour to umpires, to linesmen.

"He was lucky to even get through the first set, he should have been defaulted in about the first set. Something's got to be done about it. It's an absolute circus.

"Is it entertaining? Yeah, possibly. But it's gone to its absolute limit now."

Asked how he considered Kyrgios to be cheating, Cash said: "The gamesmanship, the stuff that he was doing. The abuse that he was giving Tsitsipas.

"Tsitsipas would make a line call and he'd go up there and he'd start complaining, he was in his face. That's a part of gamesmanship. That's the sort of stuff that he does and I think there's a limit."

Cash's criticism comes ahead of Kyrgios facing American Brandon Nakashima on Monday. That match has been given the prize billing of first up on Centre Court, despite neither man being seeded.

The tennis authorities may not approve of some of the behaviour, but they know there is a huge public fascination with the highly talented Kyrgios, which is why that match has such a prestigious slot. He is 40th in the ATP rankings, and 20-year-old Nakashima is 56th on the list.

Kyrgios is just one win away from matching his best run at Wimbledon, having reached the quarter-finals in 2014 with a win over Rafael Nadal before being beaten by Milos Raonic.

Yet Cash indicated the loudmouthed showman should face sanctions for his actions.

"I have no problem with a bit of gamesmanship, but when it gets to that level I think it's out of control, and it was," Cash said.

"The umpire had lost control, the ball kids were running across the court as Kyrgios was serving. He didn't slow down for any of that stuff.

"Tsitsipas got sucked right in, so it was entertaining, and it was fascinating, but for me it's gone too far now."

Australia expects as Ash Barty faces Danielle Collins in Saturday's grand slam final at Melbourne Park.

The world number one, from Ipswich, Queensland, will be bidding for her third grand slam singles title but a first at the Australian Open.

The wait for a home champion has been a long one, but it could soon be over.

Chris O'Neil was the last Australian winner of the women's singles, way back in 1978, while the last men's singles champion was Mark Edmondson in 1976.

Australia has hardly been starved of tennis talent over the past 40 years, but for one reason or another, the home slam has been beyond their reach.

Here, Stats Perform remembers the household names who have seen their hopes dashed in Melbourne.

Jelena Dokic

Dokic never came close in Melbourne, truth be told. Which is not to say she lacked the ability, having reached the Wimbledon semi-finals in 2000 and climbed as high as number four in the WTA rankings two years later. Dokic's career was blighted by a traumatic relationship with her overbearing and violent coach and father, Damir, whom she alleged physically abused her on many occasions. Her best performance at Melbourne Park came against all expectations, at the outset of a tour comeback in 2009 when she reached the quarter-finals, losing out there to Dinara Safina. Dokic, who is now 38 and retired from the tour, has been conducting on-court interviews during this year's Australian Open.

Lleyton Hewitt

'Rusty' won Wimbledon and US Open titles at the peak of his powers, and reached number one in the world at the age of 20. Before Roger Federer came along with different ideas, it seemed Hewitt might rule the roost in the men's game for years to come. He reached one Australian Open final, and in 2005 that was a glorious chance to secure a home major as he faced Russian Marat Safin in the final. Hewitt won the first set, but then Safin took command, winning in four. Incredibly, it would be the last grand slam men's singles final not to feature Federer, Rafael Nadal or Novak Djokovic until the 2014 US Open (Nishikori v Cilic).

Pat Cash

Cash's career peak came at Wimbledon in 1987, when he beat Ivan Lendl to capture the title before famously climbing up to the players' box. At the start of that year he almost won the Australian Open, too, when that tournament was staged on grass at Kooyong, in Melbourne's suburbs. He lost a five-set thriller to Stefan Edberg, another grass-court master, and when the tournament moved to Melbourne Park a year later, shifting to hardcourts, Cash was a finalist once more. Again, he suffered heartbreak in a deciding set, Mats Wilander denying Cash home glory, and he would never play a grand slam final again.

Samantha Stosur

Stosur, who called time on her singles career after a second-round defeat in Melbourne this year, was Australia's most recent women's singles grand slam champion until Barty came along. She triumphed at the 2011 US Open, sensationally beating Serena Williams in the Flushing Meadows final, and got to as high as number four in the world. She also reached the 2010 French Open final, but Stosur was never a factor in the business end of her home major, at least in singles. The fourth round was the furthest she ever went, but it was a different story in doubles, as she won an Australian Open mixed title in 2005, alongside fellow Australian Scott Draper. In the twilight of her career, in 2019, she teamed up with Zhang Shuai to win the women's doubles, a poignant success after so much singles frustration.

Mark Philippoussis

Philippoussis, aka 'Scud', was a US Open runner-up in 1998 and also reached the 2003 Wimbledon final, where he was the sacrificial lamb as Federer scooped the first grand slam title of his career. In Australia, though, just like Stosur, his slam peak was round four, a disappointment considering his talent and weaponry. In 1996, Philippoussis stunned the then world number one Pete Sampras in the third round in Melbourne, only to lose to lowly ranked compatriot and doubles expert Mark Woodforde in his next match. Arguably the most famous story concerning Philippoussis and the Australian Open is the widely reported rumour he was spotted kissing Anna Kournikova in an underground car park at the 2000 tournament. Both denied it. "Just good friends," was Kournikova's verdict.

Pat Rafter

Rafter won back-to-back US Opens in 1997 and 1998, as well as reaching consecutive Wimbledon finals in 2000 and 2001. A semi-final run in Melbourne in 2001, which proved to be the serve-volley master's last year on tour, was Rafter's best performance at his home slam, eventual champion Andre Agassi coming from two sets to one down to deny him a place in the title match.

Nick Kyrgios

All the talent in the world, but Kyrgios appears to be happy enough ploughing a unique furrow though his tennis career. Top five in the shot-making stakes, Kyrgios turns 27 in April and his ability has taken him to just two slam quarter-finals to date, including at the 2015 Australian Open. He was a junior champion at Melbourne Park in 2013, and has also reached the fourth round twice in the seniors. It is up to Kyrgios whether he wishes to make optimum use of his remarkable racket skills or carry on entertaining with virtuoso, but short-lived, singles runs. You wonder whether a Barty triumph could ignite this firecracker of a player.

Having seen crowds return to a range of tour events, former Wimbledon winner Pat Cash understands the disappointment of tennis moving back to behind closed doors at the Olympic Games in Tokyo.

Each of the three grand slam events to have taken place this year has been held with fans in attendance, with Centre Court seeing capacity crowds for each of the singles finals at Wimbledon. The US Open, which begins on August 30, will allow 100 per cent fan capacity at Flushing Meadows for the final major of 2021.

However, Cash does not believe the lack of spectators at the Games will have too much of an impact on the players who have elected to travel to Japan.

"Well it's unfortunate that the Olympics won't have any fans. I think that's a real disappointment," Cash told Stats Perform.

"But 95 per cent of our life is played on an empty practice court and stadiums.

"Certainly, when you're coming through, nobody's watching you. It's only when you get to Wimbledon or something that you play with crowds, and they can make a difference. We've also been playing most of the year without them.

"To go back [to no fans] it's unfortunate, but it's not something unusual for the players. The crowd certainly does make a difference. It makes a difference with attention and with the crowd roaring and whistling or whatever they want to do."

World number two Naomi Osaka, who will return to action having withdrawn from the French Open to protect her well-being and subsequently skipped Wimbledon, is one athlete who could have benefited from the home support in Japan.

Though he is unsure of how boisterous the home crowd would have been in Tokyo, Cash still feels for the 23-year-old four-time Grand Slam winner.

"With no crowds there that's disappointing for her," he added. 

"But you know, it's sort of something we've become used to on the tour - playing with empty crowds and the nerves still kick in, it is all about winning, and players tend to learn to block the crowds out quite well.

"They stay in their own world when they're on the tennis court. The urgency and the intensity of a match is not really going to change that much because the players really want this for themselves."

Wimbledon champion Ash Barty has "a great chance" of securing Olympic glory for Australia in Tokyo.

That is the view of former Wimbledon winner Pat Cash, though he warned there is plenty of scope for upsets in both the men's and women's singles.

Monica Puig claimed a surprise victory at Rio 2016 - then ranked 34th, she stunned Angelique Kerber in the final after beating Petra Kvitova and Garbine Muguruza en route to give Puerto Rico their first-ever gold medal.

Roger Federer and Novak Djokovic are two greats on the men's side who have not tasted Olympic glory, something the Serbian will look to put right this year as he pursues a Golden Slam.

Cash, though, would not be surprised to see the Olympics throw up another surprise result, even though he hopes to see compatriot Barty come out on top in the women's tournament.

He told Stats Perform: "The women's draw is very, very even. If you don't play well in one of those matches, you're out. 

"There's no such thing as an easy first round really in a tournament such as the Olympics, particularly the men’s side where it's best of three sets. So if you slip up, you're gone. 

"There's no chance of coming back from two sets to one down, because it's over. So that's trickier for somebody like Djokovic who can typically run people into the ground.

"Ash has got a great chance of winning the Olympics, but I think probably there's 30 girls who think they can do that as well and they're probably right. 

"We've seen some unusual results in the Olympics and shorter form tournaments like that, also on the men's side.

"It's very hard to say, but obviously, [Barty] is in great form and full of confidence - that goes a long way to winning a gold medal."

There have been a host of high-profile withdrawals from the tennis in Tokyo.

Rafael Nadal, Federer, Dominic Thiem, Matteo Berrettini, Serena Williams, Sofia Kenin, Simona Halep and Coco Gauff among a large list of top players who will be missing.

Some absences were unavoidable due to injuries or positive coronavirus cases but some players have opted to rest amid a hectic calendar, avoiding Japan's strict COVID-19 rules in the process.

Cash has mixed views on the subject but does feel playing at the Olympics should be seen as a rare and valuable opportunity.

"I think I think they would [look back fondly at winning a medal]," said Cash.

"It’s certainly one of the regrets in my career that I didn't play the Olympics [in 1988]. I had a niggling injury and decided to rest. 

"Looking back, I thought I could have won a medal, maybe even a gold medal. I would have probably given it a really good shot. 

"In my era it wasn't the pinnacle. I think Novak Djokovic has talked about that now, he said, ‘The main thing for me is winning slams, they're the pinnacle of our game’. 

"But to win a gold medal, it's pretty cool. You'll find that the players who do win a gold medal, if you tell the grandkids, 'I won a Wimbledon trophy' or 'I won a gold medal', they’ll go, 'Oh, where’s the gold medal?'

"Having said that, there's a lot of players who aren't playing the Olympics this year. Certainly for a few years, it was a novelty - I'm not sure if it's wearing off or not. 

"But to perform for your country, I think is an honour and we haven't had the opportunity to do that much in the last couple of years. 

"With the Davis Cup, the men's competition is really just a fading, unfortunately, dying competition, which not many people really care about any more.

"That's very, very sad, so the Olympics is often the best opportunity to represent your country."

Cash delved deeper into the dilemma players are likely to have faced.

"I wouldn't put any criticism on anybody for the personal choice after these last 18 months," he said. "It's their choice, everybody's got a different journey in this and it's part of their careers. 

"With COVID and all that sort of stuff that's going on - the bubbles - some of the stresses are unknown like being away from family and friends for months on end and not actually have any break. 

"Everybody's got their own different stories, some of them are injured, some were coming back from injury, some think 'I'm not going to make a trip to Japan' - with all the restrictions it's not going be fun. 

"It's not going to be a fun Games where you can go there and watch the other athletes. In Los Angeles [the 1984 Games] the highlight was actually to go and watch the track events, which I did.

"That's not going to happen, you're in a hotel, you're in the village or, you're gonna go straight to the tennis and back only to a certain area of the village, I think it's going to be locked down for tennis players only. 

"You may not be able to mingle with the other athletes. So I think a lot of the fun has been taken out of this. 

"But again, it's representing your country and trying to get trying to get a gold medal. So some players will go to great lengths to do that."