Novak Djokovic is unwilling to commit to January's Australian Open as the defending champion awaits confirmation on travel and entry requirements amid Victoria's vaccine mandate.

The state of Victoria, where the year's opening grand slam takes place at Melbourne Park, has introduced a vaccine mandate for professional athletes and across most industries due to the coronavirus pandemic.

The 2021 Australian Open went ahead, albeit in February instead of January, and without fans for most of the tournament following a snap lockdown of Melbourne due to COVID-19.

Last week, Australia prime minister Scott Morrison said unvaccinated players would be allowed to contest the slam if they completed two weeks in quarantine, though Victoria premier Dan Andrews dismissed those comments, insisting athletes would not be granted access unless they received the COVID-19 vaccine.

A record nine-time Australian Open champion, world number one Djokovic remains non-committal over his looming title defence.

"Well, I'm going to decide on whether I go to Australia or not after I see the official statement from Tennis Australia," Djokovic said as he prepares for the Paris Masters – his first tournament since losing to Daniil Medvedev in September's US Open final.

"Right now, we don't have any official announcement or statement. So until that's out, I won't be talking about this anymore, because I don't want to be part of the stories about the assumptions and what-ifs.

"When official condition requirements to travel to Australia and play in Australia are out, then obviously I'll see what I personally do with that, and also the bigger group of the players, you know, because the situation is obviously different in Australia than most parts of the world."

World number two Medvedev also refused to confirm his Australian Open participation.

"I always said it, that I really like Novak's answer about this. I want to keep my medical, no matter if it's about vaccine, leg injury, head injury... I want to keep my medical private for a reason," Medvedev said.

"I feel like tennis is such a brutal sport where you're always one on one against your opponent, and any information you give him can go against you.

"If you're playing Australia, it's obvious you're vaccinated. So that's why I said I'm willing to play Australia, but I won't say if you'll see me there, but we're going to see in January."

World number one Novak Djokovic said he will return to action at the Paris Masters blessed to be a more "humble" tennis player.

The Serbian makes his first appearance since his US Open final defeat to Daniil Medvedev at the ATP 1000 tournament in the French capital.

That defeat in New York cost Djokovic the chance to become only the third man to win a singles calendar slam by winning all four majors in the same year.

Djokovic also missed the opportunity to move top of the all-time Grand Slam tournament winners list and remains joint-top alongside Roger Federer and Rafael Nadal with 20 titles.

However, the 34-year-old – whose status for the 2021 Australian Open remains unknown – was phlegmatic when he reflected on his loss to Russian world number two Medvedev.

"In a most ideal scenario, I would have won all four of them," Djokovic told a media conference. "Knowing I was so close gives me great encouragement for the future, but it also makes me feel humble about my game, about my career.

"It gives me a kind of reality check where I have to go back to the practice court and really understand what needs to be done so that I could improve.

"This was not an ordinary loss considering the circumstances. I have learned over the years to deal with losses in such way that I treat them as great opportunities for growth.

"I feel that the US Open loss in the final has arrived arguably at the worst or at the best time for me, in a way.

"I'm disappointed that I lost the match, but I feel like I was blessed to experience love from the crowd and support from the stadium that I have never experienced before in my life in New York, and actually not in many places around the world.

"That kind of energy that I received from the crowd from the moment I stepped on the court until I stepped out is a win for life."

Djokovic, who has won four of the last eight Paris Masters tournaments, claimed the prospect of ending the year as the world number one ahead of Medvedev will motivate him.

Should he do so then Djokovic would leapfrog Pete Sampras for the most year-end number one finishes in history with seven.

He will face either Italian Fabio Fognini or Hungarian Marton Fucsovics having received a bye through the first round.

"The year-end number one is on the line between Medvedev and myself, and I'm in a pretty good position," added Djokovic, who has won 85 ATP tour titles.

"That's obviously the goal for the end of the season other than trying to do well in the Davis Cup with the national team. So hopefully I can have a strong finish of the season and clinch that year-end number one.

"I’m pleased to be back. I have been training really well the past couple of weeks. And I have had plenty of success in Paris over the years, so that gives me enough reason to believe that I can do well.

"The lack of match play could be dangerous, so I have to really make sure that I start off my first match very well with a good intensity and build my form."

Marin Cilic won his 20th title on the ATP Tour by battling past Taylor Fritz in the final of the St Petersburg Open on Sunday.

A decade on from lifting the trophy for the first time, Cilic outlasted his American opponent 7-6 (7-3) 4-6 6-4 in a gruelling contest lasting two hours and 23 minutes.

It took the Croatian to four tournament wins on Russian soil, the 33-year-old having also twice won the crown in Moscow, while it also saw him join truly elite company in the men's game.

Only five other active male players have won 20 or more titles: Roger Federer (103), Rafael Nadal (88), Novak Djokovic (85), Andy Murray (46) and Juan Martin del Potro (22).

"Coming 10 years after winning in 2011 and also winning now, it's so, so special for me, especially this part of my career," said Cilic. "Having now a family, two sons, I want to absolutely dedicate this trophy to my newborn son."

Cilic had the chance to reach 20 titles last week in Moscow, only to lose in straight sets to home favourite Aslan Karatsev.

With 12 aces and 78 per cent of first-serve points won, the former world number three was aggressive in his efforts to make sure this was not another missed opportunity.

After taking the first set, Cilic twice led by a break in the second but allowed Fritz to level the contest and keep alive his hopes of a first title since Eastbourne two years ago.

Fritz went a break ahead in the decider but Cilic battled back to level at 4-4. A double fault from the world number 28 gave Cilic the chance to serve out the contest, and he duly obliged, converting his first match point with a volley.

Alexander Zverev captured his fifth title of the season at the Vienna Open after defeating Frances Tiafoe 7-5 6-4 in Sunday's final.

The Olympic champion claimed more silverware in Vienna, having also triumphed in Madrid, Cincinnati and Acapulco in 2021.

The world number four, who claimed his 300th tour-level career win against Alex de Minaur earlier in the week, is now 25-2 since exiting the fourth round at Wimbledon in July.

Tiafoe was appearing in his first ATP 500 final having defeated Stefanos Tsitsipas, Diego Schwartzman and Jannik Sinner along the way.

The world number 49 stuck with Zverev during a tight opening set, in which breaks were exchanged early on.

However, the German broke again in game 12 to draw first blood, and went on to hit eight aces during the second set.

Tiafoe produced an inspired turnaround from 5-2 down in the second set of his semi-final victory over Sinner.

But there was to be no fairytale finish for the American, who was seeking a second ATP title and first since the 2018 Delray Beach Open.

Zverev subsequently held his nerve to move level with Casper Ruud on five titles for the season, the most on the ATP Tour this year.

Frances Tiafoe will face Alexander Zverev in the Vienna Open final after storming back from the brink of defeat to beat Jannik Sinner.

Sinner was on the cusp of another final after his triumph in Antwerp last weekend when he led 5-2 in the second set, but qualifier Tiafoe roared back to win 3-6 7-5 6-2 on Saturday.

Italian Sinner had moved into the last qualifying position for the ATP Finals by beating Casper Ruud to reach the semi-finals in the Austrian capital and appeared destined to extending his winning run.

The 49-ranked Tiafoe had other ideas, winning five games in a row to force a deciding set.

Tiafoe maintained his momentum, breaking twice in the final set to complete an astonishing comeback and leave seventh seed Sinner shellshocked.

Second seed Zverev earlier marched into his fifth tour-level championship match of the season with a 6-3 6-3 defeat of Spanish teenager Carlos Alcaraz.

Zverev, who this week secured a 50th tour-level win of the season and a 300th of his career, needed only 68 minutes to knock Alcaraz out.

The German said: "I finally found my rhythm from the baseline because I was really struggling.

"I didn't feel the ball well and I spent some time on the court after the match yesterday and warmed up for an hour and a half before the match today and I finally got it."

Marin Cilic and Taylor Fritz will do battle in the St Petersburg Open final following contrasting wins over Botic Van de Zandschulp and Jan-Lennard Struff respectively.

Cilic did not face a break point in a 6-3 6-3 victory over Dutchman van de Zandschulp, while fought back to defeat Jan-Lennard Struff 5-7 6-1 6-3.

Top seed Andrey Rublev crashed out of the St Petersburg Open after a straight-sets defeat by Dutch qualifier Botic van de Zandschulp in the quarter-finals.

A recent US Open quarter-finalist, world number 69 Van de Zandschlup claimed the first top-10 win of his career on Friday.

The 26-year-old also advanced to the semi-finals of an ATP event for the first time.

There, he will face 2011 champion Marin Cilic, who was a 6-4 3-6 6-3 winner over third seed Roberto Bautista Agut.

Denis Shapovalov was another big-name casualty in Russia, the second seed going down 4-6 3-6 against world number 53 Jan-Lennard Struff.

Although, there were better fortunes for fifth seed Taylor Fritz. The Indian Wells semi-finalist is yet to drop a set this week after prevailing 6-4 6-2 against John Millman.

Elsewhere, Matteo Berrettini was the victim of another upset at the Erste Bank Open in Vienna.

The Wimbledon champion went down 1-6 7-6 (7-2) 6-7 (5-7) following a two-hour 40-minute battle with Carlos Alcaraz.

Reaching his first ATP 500 semi-final, the Spanish teenager claimed another big scalp having defeated Stefanos Tsitsipas at Flushing Meadows last month.

However, second seed Alexander Zverev remained on course for a fifth title of the season, as he claimed his 300th tour-level win.

The Australian Open finalist beat Felix Auger-Aliassime 6-4 3-6 6-3, avenging his fourth-round defeat by the Canadian at Wimbledon in July.

Alexander Zverev and Jannik Sinner moved into the quarter-finals of the Vienna Open on Thursday. 

Italian Sinner beat home hopeful Dennis Novak 6-4 6-2 to set up a tantalising showdown with Casper Ruud. 

Should he win that match, Sinner will move ahead of Hubert Hurkacz in the race to qualify for this year's ATP Finals, while victory for Ruud will strengthen the Norwegian's standing. 

"It's going to be tricky," said Sinner. "He's in a better position than I am for the race. I think right now it's tough to say and tough to do because in the end you try always not to think about that, but in the end you think about that because you believe." 

Zverev was given a sterner test, eventually overcoming Alex de Minaur 6-2 3-6 6-2 in one hour and 42 minutes. The Olympic gold medallist will now face Felix Auger-Aliassime, who fought back from a set down to defeat Cameron Norrie. 

Frances Tiafoe came from a set down to upset top seed Stefanos Tsitsipas 3-6 6-3 6-4 and earn a quarter-final meeting with Diego Schwartzman after the Argentine overcame Gael Monfils 7-6 (7-5) 4-6 6-2. 

In St Petersburg, home favourite and sixth seed Karen Khachanov lost a gruelling three-set encounter to Marin Cilic. 

The Croatian, who won the title in Russia in his last appearance in 2011, was 4-1 down in the deciding set but took all five of the final games to triumph after two and a half hours on court. 

"Everybody is playing good. The tournament is great. It's the end of the season, so everybody wants to finish on a great level," said Cilic, who next faces Roberto Bautista Agut. "For me, it was great to play this kind of a match today." 

Another Russian, Aslan Karatsev, fell to John Millman 6-3 6-2. Taylor Fritz and Botic van de Zandschulp also progressed in straight sets. 

Jannik Sinner continued his push for an ATP Finals spot with a straight-sets defeat of Reilly Opelka in the first round of the Vienna Open, while Carlos Alcaraz exacted revenge on Andy Murray.

Sinner won his fourth title of what has been an outstanding season for the Italian in Antwerp last weekend and is only 110 points adrift of Hubert Hurkacz in the battle for the final place in the season-ending event in Turin.

Murray did the 20-year-old a favour by knocking Hurkacz out of the ATP 500 tournament in the Austrian capital on Monday and seventh seed Sinner eased to a 6-4 6-2 win over American Opelka two days later.

Sinner, who will overtake Pole Hurkacz if he reaches the semi-finals this week, won 93 per cent of points behind his first serve and did not face a break point in a resounding win and will play Dennis Novak in the second round.

Murray beat Alcaraz at Indian Wells this month, but the 18-year-old rising star from Spain turned the tables on the three-time grand slam champion with a 6-3 6-4 second-round win in Vienna.

Former world number one Murray struggled with his serve and was broken five times as he made an early exit.

Third seed Matteo Berrettini beat Nikoloz Basilashvili 6-7 (5-7) 6-2 6-3 to reach the third round, while Diego Schwartzman, Gael Monfils and Lorenzo Sonego moved into the second round.

In the St Petersburg Open, defending champion Andrey Rublev beat Ilya Ivashka 6-4 6-4 to reach the quarter-finals along with Denis Shapovalov, a 2-6 6-3 6-0 winner against Pablo Andujar.

Jan-Lennard Struff also moved into the last eight, with Karen Khachanov and Marin Cilic securing first-round wins.

Novak Djokovic's participation at the Australian Open has been cast in doubt once again as Victorian premier Daniel Andrews indicated the state that hosts the event will not welcome those who are not fully vaccinated against COVID-19.

Australian minister for immigration Alex Hawke revealed last week Djokovic, who has won a record nine titles at Melbourne Park, could only take part in January's tournament if he has received both jabs.

But the 20-time grand slam winner, who has declined to reveal his vaccination status, was given hope of competing after prime minister Scott Morrison said there would be exemptions should the state of Victoria – which includes Melbourne – agree.

However, responding to those comments on Wednesday, Andrews made clear his government would not apply for any sort of dispensation as it would not be fair on the other players and spectators who are fully vaccinated.

"The federal government manages the border and to the extent that anything the federal government says on this is clear, because their position has gone 180 from what the immigration minister said," Andrews said.

"What I'm making equally clear on behalf of every vaccinated Victorian who is doing the right thing... the only fair thing to do is to be very clear with every Victorian, my government will not be applying for an exemption for any unvaccinated player."

Recent reports suggested that over a third of professional players on the ATP Tour remain unvaccinated ahead of the 2022 Australian Open, which runs for two weeks from January 17.

Andrews added: "I'm not going to ask and actually require people sitting in the grandstand, people working at the event, to be vaccinated while players aren't.

"So we're not going to be applying for an exemption, so the issue is basically resolved."

Andrews also stated the same approach will be taken when Formula One returns to Melbourne in April next year.

Speaking last week, world number one Djokovic – who beat Daniil Medvedev earlier this year to win his latest Australian Open crown – told Serbian newspaper Blic: "Things being as they are, I still don't know if I will go to Melbourne.

"I will not reveal my status whether I have been vaccinated or not, it is a private matter and an inappropriate inquiry.

"Of course I want to go, Australia is my most successful grand slam tournament. I want to compete, I love this sport and I am still motivated.

"I am following the situation regarding the Australian Open... I believe there will be a lot of restrictions just like this year, but I doubt there will be too many changes."

Stefanos Tsitsipas survived a minor scare in the first round of the Vienna Open before ultimately going on to beat Grigor Dimitrov in straight sets.

It was neck-and-neck for much of the first set, with neither player losing serve, but Dimitrov appeared to have the upper hand when he got to 6-3 in the tiebreak.

Tsitsipas recovered emphatically, however, the top seed reeling off five successive points to win the set and he went on to book his spot in the second round thanks to a 7-6 (8-6) 6-4 victory. He will face Frances Tiafoe next.

"Grigor is a tough competitor and the level of tennis was really high today. We both competed at our highest [level]," Tsitsipas said afterwards.

"That was great tennis that was being played during the entire match and I got really close to my [best] offence and showed incredible attitude [in] the last game, which was the one that was the most crucial of the match."

Alexander Zverev, seeded second, was also made to work in his first-round clash with Filip Krajinovic.

While he blew the Serbian away in the first set, he found himself 5-2 down in the second as Krajinovic looked set to level the match, but Zverev scrapped his way back and then served to love to win 6-2 7-5. Alex de Minaur awaits the German.

Casper Ruud and Felix Auger-Aliassime, seeded fourth and sixth respectively, were two other high-ranking players who also secured progression, boosting their ATP Finals qualification hopes.

Ruud was pushed hard by Lloyd Harris but eventually outfought the South African in his 7-5 7-6 (7-2) win, while Auger-Alisassime made fairly light work of Ricardas Berankis 6-3 6-2.

Indian Wells champion Cameron Norrie, who is also in with a shot of reaching the ATP Finals, beat Marton Fucsovics 7-6 (7-4) 6-1 to set up a meeting with Auger-Aliassime – the British number one is 11th in the FedEx ATP Race to Turin rankings, one above his next opponent.

At the St Petersburg Open, fifth-seed Taylor Fritz was the highest-ranked player in action and he needed a little over an hour to beat Emil Ruusuvuori 6-1 6-4.

Pablo Andujar defeated Federico Delbonis to set up a meeting with second seed Denis Shapovalov, while Ilya Ivashka beat Laslo Djere for the right to tussle with tournament favourite Andrey Rublev next.

Jannik Sinner said he was "very proud" of the level he played at as he stormed to a straight-sets victory against Diego Schwartzman in the final of the ATP European Open on Sunday.

The number one seed continued his impressive form in the tournament by sweeping aside his opponent 6-2 6-2 in just 76 minutes.

Sinner was too powerful for his Argentine opponent and showed just why he is considered to be one of the rising stars of tennis with some breathtaking winners from all over the court in Antwerp, Belgium.

"I felt great on court. I moved well. I also served better, I think," the 20-year old said. "I felt great, but in tennis every day is different. You have to be careful. I think I played well the whole tournament, to be honest, from the first point to the last point.

"I like to play indoors. I tried to push the ball [through the court], which for me was important against Diego because he is moving very well. He's not missing so many shots. For me it was important trying to adapt the game somehow against him.

"I think I can be very proud about the level I played."

The top two seeds will do battle in the European Open final following commanding victories for Jannik Sinner and Diego Schwartzman on Saturday.

Sinner, the number one seed, moved into his fifth final of the season with a 6-2 6-2 defeat of Lloyd Harris in Antwerp.

The 20-year-old Italian, who is in the hunt for a maiden ATP Finals spot, dominated Harris from the baseline and saved all three break points he faced.

There were only 16 unforced errors from the racket of the composed Sinner, who will be bidding to win his fourth title of the season on Sunday.

Sinner said: "I am very happy to be in the final. I just love playing here and love playing indoors, so hopefully I can play a great match again tomorrow."

Schwartzman ended 20-year-old American Jenson Brooksby's impressive run with a 6-4 6-0 victory.

The Argentinian struck 15 winners and secured five breaks as he marched into the championship match.

Russian second seed Aslan Karatsev will come up against Marin Cilic in his first final on home soil after knocking compatriot Karen Khachanov out of the Kremlin Cup.

Karatsev beat Khachanov 7-6 (9-7) 6-1, while sixth seed Cilic – a two-time winner of the tournament in Moscow – got the better of Ricardas Berankis 6-3 6-4.

Jenson Brooksby enhanced his growing reputation and set up showdown with Diego Schwartzman in the European Open semi-finals.

The 20-year-old American, who took a set off Novak Djokovic and rattled the world number one at the US Open, is shaping up as potentially his country's biggest hope for the future in the men's game.

Californian Brooksby crushed Spain's world number 44 Alejandro Davidovich Fokina 7-5 6-0, and second seed Schwartzman awaits after the Argentinian took down another 20-year-old American, Brandon Nakashima, scoring a 6-4 6-2 quarter-final win.

Schwartzman is the man who ended Andy Murray's hopes at the tournament in Antwerp.

Brooksby, who had to win two qualifying matches to reach the main draw, said: "Tomorrow will be a great match. I'm really looking forward to it. I'll get some rest tonight and get ready to battle again tomorrow."

The other semi-final will see Italian top seed Jannik Sinner take on South African seventh seed Lloyd Harris following their respective straight-sets wins over Arthur Rinderknech and Marton Fucsovics.

There will be an all-Russian semi-final at the Kremlin Cup in Moscow, after Aslan Karatsev and Karen Khachanov won through to the final four.

Second seed Karatsev sank the hopes of Frenchman Gilles Simon, breaking serve five times on the way to a 6-4 6-3 win, while third-seeded Khachanov edged out Australian John Millman. A 7-5 7-6 (7-4) grind featured 19 aces by Khachanov, the 2018 Kremlin Cup champion, who saved four set points in the second set.

Marin Cilic thrashed Pedro Martinez 6-1 6-2 to set up a tussle with Ricardas Berankis, the Lithuanian ending Adrian Mannarino's run with a 6-2 7-6 (7-1) success. Frenchman Mannarino had stunned Russian top seed Andrey Rublev in the previous round.

Andy Murray fumed at his own mentality and "poor" attitude after falling to a straight-sets defeat to Diego Schwartzman at the European Open.

Two days on from beating Frances Tiafoe in a three-set epic, Murray fell to a 6-4 7-6 (8-6) loss to the second-seeded Argentine in Antwerp.

The three-time grand slam winner, who in January 2019 underwent hip resurfacing surgery, was 4-1 up in the first set but was reeled back in and lost out in a hard-fought contest.

Following the defeat, a frustrated Murray said: "I didn't make as many good decisions as I would have liked in the second set dealing with adversity.

"Mentally I was poor, and my attitude was poor on the court."

Murray is still slated to play in Austria and Stockholm before the season is out, while he could also enter the Paris Masters either via a wildcard entry or going through the qualifiers.

"There'll be a decision on the final Paris wildcard on Monday, but I might even play the qualis there," Murray added. 

"Sport is a results business. Play well or poorly doesn't really matter if you lose matches. You need to be winning. 

"That's what I want in the last few tournaments. They are really strong tournaments and there are no guarantees the results will come, but I want to win more matches."

Andrey Rublev's hopes of retaining the Kremlin Cup on home soil in Moscow are over after he suffered a surprise defeat to Adrian Mannarino.

Mannarino ultimately came out on top 5-7 7-6 (7-4) 6-3 but he had to do it the hard way, coming back from match point down to set up a meeting with Ricardas Berankis, who lost only tree games in a 6-2 6-1 win over Federico Coria.

Rublev was never cruising, however, as Mannarino only just fell short in the first set and then took the second to a tiebreak, which he eventually won to turn the tide.

The 33-year-old, who lost to Rublev in the final two years ago, took things up a notch in the decider and did not face a single break point as he got the job done despite the home support.

"The crowd was cheering for Andrey but that is normal," he said after reaching the quarter-finals. "I was happy to play with such a nice atmosphere.

"We have been playing for a long time without fans, so it is nice to enjoy a stadium with crowds now."

Second-seed Aslan Karatsev is now the favourite in Moscow, and the Russian had few issues in a 6-4 6-3 defeat of Egor Gerasimov.

Karatsev will face Gilles Simon next following his 6-3 6-2 win over Mackenzie McDonald, while Pedro Martinez won 6-3 6-4 over Filip Krajinovic to book his passage.

At the European Open in Antwerp, Andy Murray's hopes of winning a first ATP Tour title in two years were ended by number two seed Diego Schwartzman.

The Argentinian trailed 4-1 in the first set but fought back to win 6-4 7-6 (8-6) in his first ever match against the Scot, whose last tour triumph was in Antwerp.

In his on-court interview, Schwartzman said: "It was a pleasure to play against Andy. We had not played before and he is coming back and every week he is playing better and moving better.

"I have a lot of respect because when I grew up playing tennis, I was watching Roger [Federer], Rafa [Nadal], Andy and Novak [Djokovic] and right now playing against him is a pleasure for me."

Seventh seed Lloyd Harris is also into the quarter-finals after a straightforward 6-2 6-3 victory over Jan-Lennard Struff in just 72 minutes, Marton Fucsovics came through 6-7 (5-7) 6-3 6-1 against Roberto Bautista Agut and Brandon Nakashima edged past Henri Laaksonen 7-6 (7-5) 6-7 (5-7) 6-3 to earn the right to face Schwartzman.