Fifth seed Matteo Berrettini survived an early scare on his return from a thigh injury to progress in the second round of the Western and Southern Open in Cincinnati over Albert Ramos-Vinolas on Tuesday.

The Italian world number eight, making his ATP Tour return since losing the Wimbledon final to Novak Djokovic in July, won 6-7 (5-7) 6-3 7-5.

The Spaniard claimed the first set in a tie-break but Berrettini hit back, sending down 25 aces for the match, winning 84 per cent on his first serve.

"I'm happy for the win. I think I served really well," Berrettini said. "My strokes from the baseline weren't working the way I wanted them to, but I knew from the beginning it's been a long time since I played a match, especially on hard, so I expected to feel a little bit weird."

The match extended to two hours and 20 minutes, with the Italian utilizing his backhand slice in the final set to get the edge.

Berrettini, who has a 33-7 record for the season, will face 12th seed Felix Auger-Aliassime or Karen Khachanov in the third round.

"I'm really happy that I'm going to have the chance to play another match because that's what I need," Berrettini said. "I need to play matches. I need to get in the best shape possible."

Canadian sixth seed Denis Shapovalov suffered a shock early upset, going down to France's Benoit Paire 6-3 4-6 7-5 in the Round of 64.

Former US Open, Wimbledon and Australian Open semi-finalist Grigor Dimitrov toppled 13th seed Roberto Bautista Agut 6-3 6-4 in one hour and 21 minutes.

Fellow seed Cristian Garin also bowed out, losing 4-6 6-3 6-4 to qualifier Tommy Paul, while ninth seed Hubert Hurkacz defeated Alejandro Davidovich Fokina 6-1 6-7 (3-7) 6-1.

Marin Cilic, John Isner, Sebastian Korda, Gael Monfils, Reilly Opelka, Lorenzo Sonego and Frances Tiafoe were the other Tuesday winners.

Isner sent down his 13,000th career ace in his three-set win over Briton Cam Norrie.

Stefanos Tsitsipas has indicated he will only get the COVID-19 vaccine if it becomes mandatory to participate on the ATP Tour.

World number three Tsitsipas revealed he has not yet been jabbed against coronavirus with the tennis world divided on the issue. 

The ATP Tour have publicly encouraged players to get vaccinated, but Novak Djokovic is among the high-profile players to have stated it should not be compulsory to compete.

When asked ahead of the Western and Southern Open if he would get the vaccine, Tsitsipas told a media conference he still had reservations.

"No one has told me anything. No one has made it a mandatory thing to be vaccinated," the Greek said.

"At some point I may have to, I'm pretty sure about it, but so far it hasn't been mandatory to compete, so I haven't done it, no."

Tsitsipas received a bye through to the second round in Cincinnati, where he will play either Sebastian Korda or Laslo Dere.

The 23-year-old, who has a tour-high 45 wins this season, climbed up to third in the world rankings last week and boldly targeted overhauling Djokovic in top spot.

"The rankings are there for a reason. They signify something important," he added.

"I think that the very next step would be the number one spot, which I hope I can get to one day.”

Petra Kvitova was one of a handful of seeded players to take the court at the Western and Southern Open on Monday and came away victorious against a past champion of the event. 

The 11th-seeded Kvitova defeated 2019 Western and Southern winner Madison Keys 7-5 6-4 on a rain-plagued opening day of main-draw play at the tournament outside Cincinnati, Ohio. 

The Czech saved eight of nine break points against her serve while breaking Keys three times, and that was enough to pull out the victory. 

Kvitova's countrywoman Barbora Krejcikova, the ninth seed, made her singles debut at the WTA 1000 event with a 6-3 6-2 rout of Daria Kasatkina. 

Fifteenth seed Elise Mertens also was a straight-sets winner, taking down Nadia Podoroska 6-3 6-4, while 13th seed Jennifer Brady defeated Ekaterina Alexandrova 6-3 7-6 (7-3) in a match that finished shortly before 1 a.m. local time.

Though only Krejcikova was in action Monday, the field in Cincinnati includes nine of the top 10 players in the rankings, led by Ashleigh Barty and Naomi Osaka in their first appearances since the Tokyo Olympics. 

In other matches on the first day of play, Heather Watson defeated Aliaksandra Sasnovich 6-2 3-6 6-1, while Paula Badosa outlasted Petra Martic 4-6 6-4 7-6 (11-9) in a two-hour, 34-minute marathon. 

Yulia Putintseva breezed past Zhang Shuai 6-2 6-0, Jelena Ostapenko beat Tamara Zidansek 7-5 6-1 and Jil Teichmann downed Sorana Cirstea 6-2 6-0. 

Angelique Kerber beat Maria Sakkari 6-2 6-2, with Alison Riske matching that scoreline in a defeat of Leylah Fernandez.

Shelby Rogers won 6-4 2-1 when her countrywoman Danielle Collins retired with an injury. 

Andy Murray looked sharp in his first singles match since Wimbledon, rolling to a straight-sets win over Richard Gasquet at the Western and Southern Open. 

Murray defeated the veteran Frenchman 6-4 6-4 on a rainy opening day in Cincinnati, capitalising on a strong service game to advance. 

Murray had 14 aces to just two double faults and won 81 per cent of points on his first serve while saving four of the five break points he faced. 

A two-time champion at the ATP 1000 event, he will face the winner of Tuesday's match between Alejandro Davidovich Fokina and ninth seed Hubert Hurkacz in the second round. 

Two players who shared a birthday Monday also prevailed on their big day. 

On the day he turned 20, 11th seed Jannik Sinner defeated Federico Delbonis 6-2 7-5, while 10th seed Diego Schwartzman had to work a bit harder on his 28th birthday to down Daneil Evans 6-2 4-6 6-3. 

Elsewhere, 12th seed Felix Auger-Aliassime beat Marton Fucsovics 7-6 (7-0) 6-3, while 14th seed Alex de Minaur rallied to down Filip Krajinovic 0-6 6-4 6-4. 

Fifteenth seed David Goffin fell 6-3 6-3 to Guido Pella in the only seeded upset of the day. 

Other winners Monday included Karen Khachanov, Fabio Fognini, Lloyd Harris, Dominik Koepfer, Benoit Paire, Albert Ramos Vinolas and Mackenzie McDonald. 

Among those set to play their opening matches Tuesday are third seed Alexander Zverev, who will face Harris, and sixth seed Denis Shapovalov, who plays Paire. 

Naomi Osaka was reduced to tears on Monday in her first WTA Tour news conference since snubbing the media at the French Open.

Osaka withdrew from the second grand slam of the year at Roland Garros almost three months ago after declaring she would not fulfil press conference duties during the tournament.

The four-time major champion cited mental health concerns for reaching that decision and skipped Wimbledon before returning to action at the Tokyo Olympics on home soil.

Osaka, who revealed in Paris she had suffered "long bouts of depression" since winning the US Open in 2018, agreed to speak to the press as she prepares return to the WTA Tour at the Western and Southern in Cincinnati this week.

The world number two was emotional after being asked how she benefits from a high-media profile but does not like talking to media.

Osaka answered the question from the journalist, but the video call was paused as she cried before later resuming the press conference.

She said before pausing: "That's interesting: I would say the occasion, when to do the press conferences is what I feel is the most difficult.

"I'm actually very interested in that point of view. For me I feel this is something I can't really speak for everybody, I can only speak for myself.

"But ever since I was younger, I've had a lot of media interest on me, and I think it's because of my background as well as how I play.

"Because in the first place I'm a tennis player, which is why a lot of people are interested in me. So I would say in that regard I'm quite different to a lot of people, and I can't really help that there are some things I tweet or say that create a lot of news articles or things like that.

"But I would also say, I'm not really sure how to balance it too, I'm figuring it out at the same time as you are, I would say."

Osaka then broke down while the next question was being put to her, but was able to continue.

The 23-year-old was given a first-round bye in what will be her first WTA tournament since the French Open.

Daniil Medvedev lived up to his top-seed billing by overcoming Reilly Opelka in straight sets in the National Bank Open final.

World number two Medvedev prevailed 6-4 6-3 in Toronto on Sunday as he became the first Russian to win the ATP tournament since Marat Safin in 2000.

Medvedev now holds four of the nine ATP Masters 1000 titles, having also previously come out on top in Cincinnati, Shanghai and Paris.

He saved all four break points faced against unseeded Opelka, who stunned Stefanos Tsitsipas in the semi-finals, and needed just 85 minutes to complete the job.

Reflecting on his latest tour triumph, Medvedev said: "I could not have dreamt of this at one point.

"With Novak [Djokovic] and Rafael [Nadal] playing, it seemed like an untouchable achievement. Now I have four wins in five finals, which is a good score. I am just happy. 

"Playing Canada and Cincinnati, the goal is to win as many matches as possible. I was able to do it two years ago and I will try and do it again."

Opelka was competing in his maiden final at this level and started strongly, racing 40-0 ahead in the fourth game with some powerful hitting.

However, the 23-year-old – the first American to reach the final since Mardy Fish in 2011 – could not break his opponent as Medvedev recovered with some impressive serving to take the game.

Medvedev earned the first break in the following game and comfortably held to take the first set.

The Russian forced Opelka into errors in the second set and reeled off nine points in a row en route to breaking his opponent in the third game.

It was plain sailing from that point on as two-time beaten grand slam finalist Medvedev eased over the line to add another trophy to his collection.

Unseeded Camila Giorgi again surprised Karolina Pliskova as she earned a straight-sets win in Sunday's National Bank Open final to claim the third singles title of her career.

The world number 71 defeated Pliskova at the Viking International and the Tokyo Olympics in the past three months and prevailed 6-3 7-5 in their latest meeting in Montreal.

Giorgi, who had never previously won a trophy above 250 level or on outdoor hard courts, has now triumphed in 16 of her last 20 matches in an impressive 2021 campaign.

She lost just one set all week and will move back into the world's top 35 for the first time since May 2019 with this first tournament victory since the Linz Open in October 2018.

Fourth seed Pliskova eliminated favourite Aryna Sabalenka in the semi-finals but could not replicate that performance as she fell at the final hurdle in a tournament for the third time this year.

Giorgi broke the former world number one for the first time in a lengthy fifth game and took the first set when Pliskova double faulted and sent a forehand wide in the final game.

Pliskova double faulted six times across the match, which lasted one hour and 40 minutes, including in the fourth game of the second set to put her opponent in complete control.

The Czech was given hope when earning her first break of serve in the following game, but she was let down by some forehand errors in the 12th game and Giorgi took her second championship point to seal an emotional win.

Roger Federer will not take part in the upcoming US Open after the 20-time grand slam winner announced he is to undergo knee surgery that will rule him out for "many months".

The 40-year-old has not been in action since losing to Hubert Hurkacz in a Wimbledon quarter-final in July and has completed only five events this year.

Federer underwent two operations on his right knee in 2020 and requires another procedure that the legendary Swiss hopes will give him a chance to return to the court.

"I just wanted to give you a bit of an update on what's been going on since Wimbledon," Federer, who won the most recent of his five titles at Flushing Meadows in 2008, posted in a video message on his Instagram page on Sunday.

"As you can imagine, it's not been simple. I've been doing a lot of checks with the doctors as well on my knee, getting all the information as I hurt myself further during the grass-court season and Wimbledon.

"That's just not the way to go forward, so unfortunately they told me for the medium to long term to feel better, I will need surgery. I decided to do it.

"I'll be on crutches for many weeks and also out of the game for many months, so it's going to be difficult of course in some ways.

"But at the same time I know it's the right thing to do because I want to be healthy, I want to be running around later as well again and I want to give myself a glimmer of hope to return to the tour in some shape or form."

Federer, now ranked number nine in the world, missed more than a year of action after first having his knee operated on shortly after the 2020 Australian Open.

"I am realistic, don't get me wrong," he said. "I know how difficult it is at this age right now to do another surgery and try it. 

"But I want to be healthy, I will go through the rehab process I think also with a goal while I'm still active, which I think is going to help me during this long period of time."

Federer added: "Also a big thank you already now for all of your messages that are going to be coming in because you guys are always incredible. 

"You always think of me. Some of you suffer with me. I'll update you as I move along with my rehab. I wish you all the best and I'll check in with you soon."

The US Open in New York begins on August 30, with Dominic Thiem looking to retain his title.

Top seed Daniil Medvedev will face Reilly Opelka in the National Bank Open final after the American stunned Stefanos Tsitsipas in a three-set classic in Saturday's semi-finals.

World number 32 Opelka fought back from a set down in Toronto to knock out favoured third seed Tsitsipas in two hours and 32 minutes.

The 23-year-old American triumphed 6-7 (2-7) 7-6 (7-4) 6-4, booking a spot in his first ATP Masters 1000 final.

Opelka sent down 17 aces but also hit 27 groundstroke winners in the shock victory over 2021 Australian Open semi-finalist Tsitsipas who had beaten in-form Casper Ruud in the quarters.

"I played great," Opelka said in his on-court interview. “These courts suit my game, it is no coincidence that John Isner is in the other semi-final.

"Stefanos has definitely improved his returning. Come 5-5 in the first set, a lot of balls started to come back. He is a thinker and has a high tennis IQ, so it was expected, but that is what separates him from the rest of the pack."

Opelka was aided by an excellent first serve percentage of 72 per cent, winning 62 of 81 points when he made his first serve.

Both first two sets went to tiebreaks, with Tsitsipas failing to generate a break point until the third set. Opelka made the first break of the match in the seventh game of the third set and held serve twice after to seal victory.

World number two Medvedev cruised into the decider with a commanding win over John Isner in less than an hour.

Medvedev, who was runner-up in Toronto in 2019, won 6-2 6-2 over the big-serving American, with the match totaling 54 minutes.

Isner could only manage four trademark aces for the match, while the Russian had 11 and broke the American four times from seven opportunities.

Karolina Pliskova will face unseeded Italian Camila Giorgi in the National Bank Open final after beating top seed Aryna Sabalenka in the last four.

An intriguing semi-final pitted two of the favourites against one another in Montreal and it was Pliskova, the fourth seed, who came out on top 6-3 6-4.

The Wimbledon finalist broke early in the first and then clinched the set on Sabalenka's serve, too, although she was made to work a little harder in the second.

Pliskova fell behind in the seventh game, but she responded by winning three straight games to wrap up victory.

"It's an amazing feeling to be in another final this year," Pliskova said.

"I think I was super solid today. I just did everything what I was supposed to do to win this match, played smart.

"My serve was pretty good, I have to say."

Indeed, the Czech landed 71 per cent of her first serves in – with 10 aces to two double faults – helping her to win 69 per cent of her service points.

World number 71 Giorgi progressed to the decider with a three-set win over Jessica Pegula in two hours and 11 minutes.

The 6-3 3-6 6-1 win means the Italian qualified for her first career WTA 1000 final.

Giorgi had toppled seventh seed Petra Kvitova, ninth seed Elise Mertens and 15th seed Cori Gauff on her route to the decider.

Roger Federer "is a little uncertain" when he will be back in action just over a fortnight before the US Open gets under way.

The 20-time grand slam winner withdrew from both the Canadian Open and Cincinnati Masters this month as he continues to recover from a knee injury.

Federer has not played since losing to Hubert Hurkacz.in a Wimbledon quarter-final in July and has completed only five events this year.

The legendary Swiss, who underwent two operations on his right knee last year, is unsure if he will feature at Flushing Meadows.

He told Swiss newspaper Blick: "I haven't done anything for a long time because of my knee. After Wimbledon, I had to let everything sink in first.

"This week I'll meet my doctors and my team and then we'll see what happens next. At the moment everything is still a little uncertain."

Federer, who celebrated his 40th birthday last Sunday, remains upbeat despite such uncertainty.

He said: "You have to adapt. It has always been like this in my career. Factors change: degree of awareness, successes, experiences, identity and now just that.

"I'm a quiet guy who takes things with a sense of humour. I always see the good in every situation. If it's not good right now, I know it will get better and it could be a lot worse.

"I am doing very well. My family is healthy. I just turned 40 and I'm still active. Who would have thought it? Certainly not me. I am totally at peace with myself and I am sure that there will be a lot more beautiful things to come."

Novak Djokovic drew level with Federer and Rafael Nadal on 20 major singles titles by winning Wimbledon and the world number one will be bidding to complete a calendar Grand Slam in New York.

Local hope and reigning champion Bianca Andreescu blew an early lead as she was toppled by Ons Jabeur in the Round of 16 at the National Bank Open in Montreal.

Tunisian 13th seed Jabeur defeated the Canadian second seed 6-7 (5-7) 6-4 6-1 in two hours and 39 minutes on Thursday.

The come-from-behind triumph was the second time in two matches that the Tunisian has rallied from a set down to win after beating Daria Kasatkina in three.

Jabeur had twice been a break up in the opening set before Andreescu claimed it in an tiebreak.

The 26-year-old Tunisian, who made the Wimbledon quarter-finals this year, responded by breaking at 5-4 to win the second set.

After Andreescu had an injury scare after landing awkwardly on her left foot late in the second set, Jabeur dominated the third, finishing by winning eight of the final nine games.

Jabeur finished with 9-3 aces and was more effective on serve, going at an 81.6 win percentage on her first serve (40 from 49 points).

The lower side of the draw has opened up for the Tunisian who will face Jessica Pegula in the quarter-finals after the unseeded American defeated countrywoman Danielle Collins 6-4 3-6 7-5.

Two-time Wimbledon champion and seventh seed Petra Kvitova was knocked out in a shock by Italian Camila Giorgi in straight sets.

Giorgi, ranked 71st in the world, won 6-4 6-4 in one hour and 36 minutes and will face Cori Gauff in the quarter-finals after she had another walkover against Johanna Konta.

Top seed Aryna Sabalenka had no such problems, cruising past Canadian Rebecca Marino 6-1 6-3 inside an hour.

Sabalenka sets up a quarter-final clash with fellow Belarussian and two-time Australian Open winner Victoria Azarenka.

Azarenka got past Greek 11th seed Maria Sakkari in three sets, 6-4 3-6 7-6 (7-2).

Fourth seed Karolina Pliskova got past Amanda Anisimova 6-1 7-6 (10-8) and will play Sara Sorribes Tormo in the last eight after she won in three sets over Katerina Siniakova.

Casper Ruud continued his excellent winning streak while Stefanos Tsitsipas made it a birthday to remember at the National Bank Open in Toronto.

Tsitsipas turned 23 on Thursday and marked the occasion with a 6-3 6-2 win over Karen Khachanov.

The Greek star was presented with a cake by tournament officials after his win, as the crowd serenaded him with a chant of 'happy birthday'.

It marks a significant improvement on when Tsitsipas turned 20. On that occasion, he lost the 2018 final of this event to Rafael Nadal.

Next up for Tsitsipas is Casper Ruud, who poked fun at his critics after he eased into the quarter-finals.

Ruud, the world number 12, won three titles on clay courts in July and has now continued that form in the ATP Masters 1000 event.

Playing on a hard court has proved no challenge for the in-form Norwegian, who wrote 'Hard Courts' with a smile underneath on the camera after his 6-4 6-3 victory over Dusan Lajovic on Thursday.

"I have seen a lot of people questioning my ability to play on hard court, so I just thought it was funny to write a little note," Ruud said in a news conference.

"I think it's fun to play on hard courts. Even though I (have achieved) most of my best results on clay, my best slam result is from this year’s Australian Open (where he reached the Round of 16), so I think it's a surface that also can suit my game well even though this year has been mainly clay.

“I think I'm motivated to come back to the hard courts. I have had two very good matches here. It's a great start for me to the hard-court swing."

Ruud, in the hunt for his fifth title of 2021, has won the only previous meeting between the duo.

"[I am] looking forward to that battle," Tsitsipas said. "We have played each other in the past. Not an easy guy to play against. Looking for a change, looking for a switch-up this time."

However, there was no place in the last eight for world number seven - and Olympic gold medallist - Andrey Rublev, who went down 7-5 7-6 (7-5) to American John Isner.

Fresh from a triumph in Atlanta, 36-year-old Isner has looked sharp all week and has now won eight successive matches.

It brings up a third quarter-final appearance for the world number 30 in Canada, and he will play French 11th seed Gael Monfils after he got past lucky loser Francis Tiafoe 6-1 7-6 (7-2). Monfils will be competing in his first ATP Tour quarter-final in 18 months.

Top seed Daniil Medvedev proved too good for Australian qualifier James Duckworth, winning 6-2 6-4 in one hour and eight minutes.

Medvedev was in ominous form on the hard court, sending down 10-1 aces and winning 27 of 32 points on his first serve.

The Russian world number two will play seventh seed Hubert Hurkacz who fought back to win 6-7 (7-9) 6-4 6-4 over Nicolas Basilashvili.

Eighth seed Diego Schwartzman lost in three sets to 10th seed Roberto Bautista Agut after the Spaniard saved three match points.

Bautista Agut will next play Reilly Opelka who came from behind, and also saved a match point, to win over Lloyd Harris in three.

Two-time Grand Slam winner Simona Halep's return to the WTA Tour ended in defeat to American Danielle Collins in almost three hours in the National Bank Open in Montreal on Wednesday.

World number 28 Collins triumphed 2-6 6-4 6-4 over the sixth seed Romanian, with the second-round match lasting two hours and 55 minutes.

Halep, who is a two-time winner in Montreal, was returning to the Tour for the first time in three months since suffering a calf tear against Angelique Kerber in Rome.

Collins, who has won titles recently in San Jose and Palermo, loomed as a tough first-up test for Halep, who broke twice to win the first set 6-2 as she generated eight break points to one.

The game turned from then on, as Collins sent down 4-1 aces in the second set and finished with 38 winners for the match.

Tokyo 2020 bronze medalist and third seed Elina Svitolina was bundled out in a second-round shock, losing 3-6 6-3 6-2 to Briton Johanna Konta.

Svitolina boasted a 5-0 record against Konta heading into the match but was beaten in a two-hour-and-11-minute struggle.

Top seed Aryna Sabalenka defeated former U.S. Open champion Sloane Stephens in three sets to secure her third-round spot.

Sabalenka fought back from the brink, rallying to win the last five games and triumph 7-6 (7-4) 4-6 6-4 over the American wildcard in a two hours and 25 minutes.

Fourth seed Karolina Pliskova came from behind to win 4-6 6-3 7-6 (7-2) over Donna Vekic, while Jessica Pegula also fought back after a slow start to topple 10th seed Anastasia Pavlyuchenkova 1-6 6-3 6-2.

Greek 11th seed Maria Sakkari won in three sets 6-4 6-7 6-4 over Veronika Kudermetova, while 13th seed Ons Jabeur responded after a lopsided first set to win 2-6 6-3 6-4 over Daria Kasatkina.

Cori Gauff progressed after being 5-0 up as Anastasia Potapova retired, while Amanda Anisimova, Camila Giorgi, Rebecca Marino and Sara Sorribes Tormo all won too.

Canadian local hope Marino will take on top seed Sabalenka, while Gauff faces Svitolina's conqueror Konta.