Sixth seed John Isner sent down an Atlanta Open joint record 36 aces as he overcame countryman Jeffrey John Wolf in three sets on Tuesday.

World number 35 Isner was dominant on his first serve, winning 6-4 6-7 (3-7) 6-4 to claim a spot in the second round where he will face Jack Sock who beat Ricardas Berankis in three.

Isner's 36 aces equaled the previous Atlanta Open record set by Sam Querrey on Monday in his three-set win over Peter Gojowczyk.

American fifth seed Taylor Fritz also progressed on Tuesday with a 6-3 6-4 victory over Russian Evgeny Donskoy.

French seventh seed Benoit Paire got past Japan's Yasutaka Uchiyama 7-5 6-7 (2-7) 6-4, while enigmatic Australian Nick Kyrgios beat South African Kevin Anderson 7-6 (7-4) 6-3.

Teenage American talent Brandon Nakashima knocked out Trent Bryde, while Australian Chris O'Connell beat Denis Kudla and Finland's Emil Ruusuvuori got past Mackenzie McDonald 7-6 (7-3) 7-5.

Nakashima, who got a special exemption entry into the Atlanta Open, next takes on top seed Milos Raonic.

Host nation Japan remain top of the Olympic Games medal table, one gold medal clear of the United States and China, thanks to another two gold medals on Tuesday in Tokyo.

Japan now have 10 golds at the Games, five of which have come in Judo, despite home favourite Naomi Osaka crashing out to Czech world number 42 Marketa Vondrousova in the women's singles tennis.

The USA extended their gold medal count to nine, with 17-year-old Lydia Jacoby stealing the headlines courtesy of gold in the 100m breaststroke – their third in the pool so far – though they had to settle for silver in softball as they lost to table-toppers Japan.

China, who have dominated the shooting to win eight medals in nine events, picked up three more golds with success in the 10m air pistol mixed event, the 10m air rifle mixed event and the women's 10m synchronised platform - their second diving gold in Tokyo.

The Russian Olympic Committee remain fourth with seven golds after winning the day's big event, the women's team artistic gymnastics, but that was overshadowed due to American Simone Biles withdrawing due to concerns over her mental health.

The Russians surprised in the pool, too, with Evgeny Rylov claiming 100m backstroke gold that forced defending Olympic champion Ryan Murphy to settle for bronze – that result represented the USA's first backstroke defeat since the 1992 Barcelona games.

After team-mate Adam Peaty's call for a British gold surge, Tom Dean and Duncan Scott made history by winning the first British swimming one-two since 1908 in the 200m freestyle.

Dean and Scott's swimming achievements capped a positive day for Great Britain that saw them collect six medals in total to stay in fifth place.

Meanwhile, Flora Duffy made history for Bermuda with gold in the women's triathlon as the tiny Caribbean island became the smallest country to ever win Gold at the Summer Games.

Simone Biles said she had put her "mental health first" after missing out on adding a fifth Olympic gold medal to her collection following an early withdrawal from the women’s team final.

The 24-year-old gymnastics icon revealed she was “dealing with things internally” after a disappointing performance on the vault.

Biles posted the lowest score of the first rotation on Tuesday as she landed awkwardly after failing to execute an Amanar, while only completing a Yurchenko 1.5 twist.

After she subsequently withdrew, Team USA had to settle for a silver medal behind the Russian Olympic Committee while Great Britain completed the podium.

Biles admitted that she was "fighting demons", explaining: "I just don't trust myself as much as I used to. I don't know if it's age. I'm a little bit more nervous when I do gymnastics. I feel like I'm also not having as much fun."

She added: "I say, 'put mental health first'. Because if you don't, you won't enjoy sport and won't succeed as much as you want to.

"So it's okay sometimes to sit out the big competitions to focus on yourself, because it shows how strong a competitor and person that you really are, rather than just battling through it."

OSAKA STUNNED

The big names continue to tumble in the women’s singles tennis event, with second seed Naomi Osaka defeated in straight sets.

The home favourite, who lit the Olympic cauldron on Friday, was denied a place in the quarter-finals after being ousted 6-1 6-4 by world number 42 Marketa Vondrousova.

This event marked Osaka’s first competitive tennis in two months since her early withdrawal from the French Open at the end of May, citing mental health issues.

The world number two is the latest of the big names to fall at the Tokyo Games, with top seed Ash Barty and third seed Aryna Sabalenka also suffering early exits.

"Of course, it's one of the biggest wins of my career," Vondrousova said. "Naomi is a great player, so I knew it would be a tough match. 

“I'm very happy with my play. I played amazingly in the first set, and then the second set was really tough. I'm just happy to be through."

ARGENTINA RECOVER TO SEE OFF SPRINGBOKS

Argentina recovered from a dreadful start to beat South Africa and book their place in the rugby seven semi-finals.

Trailing 7-0 after just under two minutes, the Pumas were then reduced to six men when Gaston Revol - who was reduced to tears - was shown a straight red card.

Nevertheless, they demonstrated tremendous resilience and character before eventually running out 19-14 winners.

Argentina will play Fiji in the last four after the reigning Olympic champions swept Australia aside 19-0.

Great Britain stormed back from 21-0 down to beat the USA, scoring four tries to secure a dramatic 26-21 victory.

Team GB will play New Zealand, who eased to a 21-10 success over Canada.

Federico Delbonis and Laslo Djere crashed out of the Generali Open in the first round on Tuesday.

Fifth seed Delbonis and sixth seed Djere were the highest-ranked players in action on day two, but both fell to surprise defeats.

Delbonis, a recent semi-finalist at the Hamburg European Open, was convincingly beaten 6-2 6-4 by Arthur Rinderknech.

Frenchman Rinderknech fired down 10 aces and was only broken once in the contest.

Djere, meanwhile, put up more of a fight but ultimately succumbed to Daniel Altmaier, who won 4-6 6-3 6-3 in a battle lasting two hours and 10 minutes.

World number 50 Djere had also made the semi-finals in Hamburg and followed that up with another run to the last four at the Swiss Open Gstaad.

But his run of form came to an end as German Altmaier – who himself enjoyed a semi-final run in Croatia last week – booked a last-16 tie meeting with Marco Cecchinato after breaking Djere on six occasions.

Cecchinato had beaten Radu Albot in straight sets to reach the next round while qualifier Jozef Kovalik saw off Jaume Munar with a 6-4 6-4 victory.

The top four seeds, including number one Casper Ruud, will begin their campaigns at the ATP 250 event in Kitzbuhel on Wednesday.

Kei Nishikori was as surprised as anybody by Naomi Osaka going out of the Tokyo Olympics, but stressed it did not add to pressure on his shoulders.

Japan's two standard-setters in tennis are at opposite ends of their careers, with Nishikori seemingly in a slow decline and Osaka expected to add significantly to her four grand slams.

But the focus on the Japanese public looks set to switch to Nishikori for the rest of the tennis, after he reached the last-16 stage with a 7-6 (7-5) 3-6 6-1 win over American Marcos Giron on Tuesday.

Former world number four Nishikori and Ben McLachlan are through to the doubles quarter-finals too, which may be a likelier route to a medal.

Nishikori already has a bronze to his name from the 2016 Games, where he beat Rafael Nadal in the third-place match.

When asked whether he felt expectations shifting from Osaka on to his shoulders, after she lost to Marketa Vondrousova, Nishikori said: "Not really. I just need to focus on what I have to do on the court.

"It's very sad, of course, that Naomi lost and a surprise. But I knew she had a lot of pressure, this is her first time in the Olympics and I know it's not easy.

"I didn't see her match today, so I cannot say much."

Should Nishikori, now down at 69th in the rankings, beat Ilya Ivashka of Belarus on Wednesday, that could set up a quarter-final against hot favourite Novak Djokovic.

REVENGE FOR VILLAGE FAN TSITSIPAS

It was a weary Stefanos Tsitsipas who was pummelled in the first round of Wimbledon by Frances Tiafoe last month. On Tuesday, a more predictable outcome manifested as Greece's great hope scored a 6-3 6-4 victory over his American opponent.

That loss in London came barely a fortnight after Tsitsipas suffered a heartbreaking loss to Djokovic in the French Open final, from two sets up, and he was succinct with his verdict about what was different this time.

"Concentration and attention levels," was the Tsitsipas assessment.

Next for him is a testing third-round tussle with French shot-maker Ugo Humbert, and Tsitsipas will want to hang around, having been charmed by the Olympic Village experience after so long in the tennis bubble.

"It's a different contrast, it's a different approach completely," Tsitsipas said. "I've made friendships, connected with some other athletes. It's nice to be able to experience something like this. I find the Olympics are really a nice sports event.

"I met a big tennis enthusiast from India. He's doing shooting and we became good friends. I met some of the other Greek athletes, table tennis players, and rowers from different countries."

BRILLIANT BROADY

Liam Broady was a late addition to the Olympics draw and is making the most of the opportunity, with the unheralded British left-hander scoring a terrific 7-5 3-6 6-3 second-round win over Wimbledon semi-finalist Hubert Hurkacz.

Frenchman Jeremy Chardy awaits Broady after beating Russian Olympic Committee's Aslan Karatsev in three sets.

There were also wins on Tuesday for Karatsev's countryman Karen Khachanov and Argentinian Diego Schwartzman, while Wednesday's programme features the entire third-round line-up, including Djokovic's clash with Spain's Alejandro Davidovich Fokina.

Naomi Osaka was never preordained to win gold at the Tokyo Olympics but it had felt that way until she ran into Marketa Vondrousova.

The surprising 6-1 6-4 loss that a lacklustre Osaka suffered on Tuesday could be explained away by the fact the 23-year-old had not played any competitive tennis since pulling out of the French Open at the end of May.

All the same, it was a major upset as world number 42 Vondrousova took out the highest remaining seed in the draw – the Japanese star who lit the Olympic cauldron on Friday.

Osaka's exit, after previous shock defeats for top seed Ash Barty and number three Aryna Sabalenka, has raised the prospect of a shock champion, just as occurred five years ago at the Rio Games when Monica Puig of Puerto Rico caused a sensation.

Now at the quarter-final stage, there is one former grand slam champion left in the field and two finalists at that level, but it really looks like anyone's title.

VONDROUSOVA SENSES AN OPPORTUNITY

It was remarkably straightforward for Vondrousova at Ariake Tennis Park, as she cruised through the opening set and soon reeled in Osaka's early break in the second.

Osaka saved two match points when serving to stay in the contest, but not a third, planting a backhand wide.

Considering Vondrousova reached the French Open final two years ago, in front of packed grandstands rather than the empty seats in Tokyo, it was no surprise she hesitated when asked whether this win over Osaka was the biggest of her career. It probably doesn't have that cachet, good a win though it was.

"Of course it's one of the biggest," Vondrousova said.

"Naomi is a great player, she has so many grand slams, so I knew it would be a tough match. But I'm just very happy with my play. I played amazingly in the first set, and then the second set was really tough. I'm just happy to be through.

"I think she was struggling a bit with my serving. Also, I use drop-shots very well. I'm just very happy with my game today."

She faces Spain Paula Badosa next and said: "It's very open now. I think every girl is playing really well. Now it's the quarter-final, so we'll see."

HAS SVITOLINA'S TIME ARRIVED?

A fixture in the top 10 over recent seasons, Svitolina has been unable to transfer her regular tour form onto the major stage on a consistent basis.

Maybe the Olympics will be a platform towards success on that stage, with Svitolina now the highest seed remaining in the draw, at number four. The Ukrainian is also on a high on the personal front, having married French tennis star Gael Monfils shortly before heading to Tokyo.

Two semi-finals, at Wimbledon and the US Open in 2019, have been her deepest runs in the majors, and this season has been one of diminishing returns, with a fourth-round run in Australia followed by a third-round Roland Garros exit and a round-two loss at Wimbledon.

Svitolina beat Maria Sakkari of Greece 5-7 6-3 6-4 on Tuesday, setting up a quarter-final against Italian Camila Giorgi who won 6-4 6-2 against Wimbledon runner-up Karolina Pliskova.

"I don't think I'm a favourite because there are lots of good players here and everyone is quite equal," Svitolina said.

A MUG SHOT?

Should Spain's Garbine Muguruza be considered the favourite from this point? With French Open and Wimbledon titles in her trophy room, Muguruza has shown she has what it takes to triumph on a big stage, and a clinical 6-4 6-1 win over Belgian Alison Van Uytvanck on Tuesday was just the job.

She goes on to face Elena Rybakina of Kazakhstan, who edged past Croatian Donna Vekic.

Belinda Bencic of Switzerland caused a surprise by ousting the in-form reigning French Open champion Barbora Krejcikova, springing a 1-6 6-2 6-3 win that means there will be no repeat of the Roland Garros final in the quarter-finals.

That had been on the cards, but Bencic will be the player who takes on Anastasia Pavlyuchenkova for a place in the final four.

Pavlyuchenkova scored an impressive 6-1 6-3 victory over Sara Sorribes Tormo of Spain, the player who knocked out Barty in round one.

Russian Olympic Committee's Pavyluchenkova is looking to harness the form that took her to a maiden slam final, describing her Paris run as "a great experience to have".

"But every week is a new week and this is a new event," said the 30-year-old. "The Olympic Games is a very special event. It's different. It's nothing like the others."

Andy Murray said the quad injury that ruled him out of defending his men's singles title at Tokyo 2020 has not been troubling him in matches, but his withdrawal was due to concerns over results showing up in scans.

The Olympic champion in 2012 and 2016 opted to pull out of the singles prior to his scheduled first-round showdown against Felix Auger-Aliassime on Sunday. 

Instead, Murray decided to continue in the doubles alongside Joe Salisbury, where the pair made the quarter-finals on Tuesday by beating German duo Kevin Krawietz and Tim Puetz 6-2 7-6 (7-2).

It means Murray remains on track for a third straight Olympic gold and he offered a bit of insight behind his decision not to play in the singles.

"I've had a bit of an issue with my quad," he said.

"It's actually not really been causing me many issues on the court like in practice or anything, there was just some stuff showing on the scans that made all the medical team a bit wary about it.

"I said to Joe that if he picked me to play doubles with him then I'd prioritise the doubles over the singles if I had any physical issues and that was the case. 

"It's disappointing for me because I do feel like I've been playing well, and I've loved the Olympics and I would've liked the opportunity to defend my title. 

"But that wasn't to be and now all the focus and energy goes towards the doubles and to try our best to get a medal there."

Marin Cilic and Ivan Dodig await Murray and Salisbury in the last eight.

Naomi Osaka saw her Tokyo 2020 gold medal hopes go up in smoke after a painful defeat and admitted: "This one sucks more than the others."

The world number two had seen top-ranked Ash Barty bounced out in the first round, and the face of Japan's Games looked primed for a run deep into the tournament.

But the prospects of home glory in women's tennis were dashed in round three when Osaka crumbled 6-1 6-4 to Marketa Vondrousova of the Czech Republic.

Osaka, who lit the Olympic cauldron in Friday's opening ceremony, was left scrambling for answers as to why she underperformed.

"How disappointed am I? I mean, I'm disappointed in every loss, but I feel like this one sucks more than the others," she said.

"I definitely feel like there was a lot of pressure for this. I think it's maybe because I haven't played in the Olympics before and for the first year [it] was a bit much."

Asked what went wrong against the world number 42, Osaka said: "Everything – if you watch the match then you would probably see. I feel like there's a lot of things that I counted on that I couldn't rely on today."

There were certainly mitigating circumstances that the 23-year-old might have pointed to, given she had not played since the French Open before heading into the Olympics.

Osaka pulled out of Roland Garros after winning through her first-round match, citing anxiety and pointing to episodes of depression as she explained why she refused to take part in news conferences during the tournament.

Her declarations in Paris came after the four grand slam tournaments warned she could be thrown out of their events if she persistently refused to talk to the media.

Already a four-time grand slam winner, Osaka has found plenty of public support and there was criticism of the tennis authorities for their stance.

To many in Japan, she can do little wrong, although she could also do little right against Vondrousova. Osaka had 32 unforced errors to just 10 from Vondrousova, who also hit more winners.

After saving two match points, Osaka swung a backhand wide on a third to seal her exit.

Despite her disappointment, Osaka felt she had given a reasonable account following a recent absence from the tour, which saw her miss Wimbledon.

But the Games called for more than that, and it was a deflated Osaka who spoke afterwards, explaining how the pressure on her shoulders proved overbearing.

"I've taken long breaks before and I've managed to do well," she said. "I'm not saying that I did bad right now, but I do know that my expectations were a lot higher.

"I feel like my attitude wasn't that great because I don't really know how to cope with that pressure, so that's the best that I could have done in this situation."

Naomi Osaka saw her Olympic gold medal dream shattered by a third-round defeat to Marketa Vondrousova at Tokyo 2020 on Tuesday.

Osaka lit the Olympic cauldron on Friday and was widely hailed as the 'face of the Games', with enormous expectation that she would go on to triumph for hosts Japan.

The early exit of world number one Ash Barty seemed to help her case, but Osaka lost 6-1 6-4 to her Czech opponent in an hour and eight minutes.

Osaka played a dismal opening set but then looked to have raised her game a notch in the second, establishing an early break.

However, that did not herald a full-blown fightback as former French Open runner-up Vondrousova soon got back on level terms and forced Osaka to serve to stay in the contest.

From 15-40, Osaka saved two match points, but Vondrousova soon had a third opportunity and her spirited defence won out.

Osaka flung a backhand wide this time and Vondrousova had her prized scalp, securing a place in the quarter-finals at the expense of the world number two.

It was an untidy performance from Osaka who made 32 unforced errors to just 10 from Vondrousova.

This was Osaka's first tournament since pulling out of the French Open at the end of May, in the wake of a first-round win. She cited depression and anxiety issues in Paris after announcing she would not take part in news conferences during the tournament.

Japanese superstar Naomi Osaka crashed out of the Tokyo Olympics tennis with a 6-1 6-4 defeat to Czech world number 42 Marketa Vondrousova.

Osaka, who lit the flame at Friday's opening ceremony, had won her opening two matches but bowed out in straight sets, with Vondrousova reaching the quarter-finals.

In the first set, Vondrousova dominated on her first serve and broke three times, before the Japanese hit back with an early break in the second. But the Czech fought back to win, with Osaka finishing with 32 unforced errors to just 10 by her opponent.

"Of course it's one of the biggest wins of my career," Vondrousova said. "Naomi is a great player, she has so many grand slams, so I knew it would be a tough match. I'm very happy with my play. I played amazingly in the first set, and then the second set was really tough. I'm just happy to be through."

World number two Osaka joins top seed and Wimbledon champion Ash Barty in being eliminated early at the Tokyo Games.

In the men's singles second round, fourth-ranked Greek Stefanos Tsitsipas eased past American Francis Tiafoe 6-3 6-4, avenging a shock Wimbledon defeat.

DUFFY DELIGHT

Flora Duffy won Bermuda's first-ever Olympic gold medal with victory in the women's triathlon on Tuesday at Odaiba Marine Park.

The four-time Olympian failed to finish in Beijing, came 45th in London and improved to eighth in Rio de Janeiro.

Duffy took the Tokyo title in a time of one hour, 55 minutes and 36 seconds, finishing more than a minute ahead of Britain's Georgia Taylor-Brown who took silver, with USA's Katie Zaferes claiming bronze.

“It's always been my dream to race at the Olympics and be a professional athlete with the goal of being an Olympic champion," Duffy said.

"That's not the easiest thing to do regardless of where you're from. Bermuda is a small country, but it's really passionate about its sport.

“I'm so grateful that I could achieve a personal dream here of winning an Olympic medal, but this is bigger than me, this is going to inspire the youth of Bermuda and everyone back home that competing on the world stage from a small island is really possible."

The 33-year-old broke clear in a group of seven early in the bike stage, before dominating the 10km run.

Bermuda, which has a population of just over 70,000, had only claimed one medal previously in Olympic history, a bronze in 1976.

MCKEOWN BREAKS OLYMPIC RECORD

Australia secured a second gold medal in the pool as Kaylee McKeown broke the Olympic record in the women's 100m backstroke.

McKeown won in 57.47, finishing ahead of Canada's Kylie Masse by 0.25 seconds, with USA's Regan Smith taking bronze. Masse had led at the turn.

In the men's 100m backstroke, Russian Olympic Committee claimed a one-two finish as Evgeny Rylov edged out countryman Kliment Kolesnikov, who holds the 50m world record. Ryan Murphy, who is the world record holder across 100m, claimed bronze.

Great Britain's Tom Dean won the men's 200m freestyle by 0.04, marginally ahead of compatriot Duncan Scott, with Brazil's Fernando Scheffer coming in third. The result meant two British male swimmers stood on the same Olympic podium for the first time since 1908.

World record holder Lilly King finished third as US teenager Lydia Jacoby triumphed in the women's 50m breaststroke. South Africa's Tatjana Schoenmaker claimed silver.

CHINESE PAIR ON TARGET

China claimed another gold medal in the final of the 10m air pistol mixed team at the Asaka Shooting Range.

China's Ranxin Jiang and Wei Pang won 16-14 over Russian Olympic Committee pair Vitalina Batsarashkina and Artem Chernousov.

Ukraine duo Olena Kostevych and Oleh Omelchuk won the bronze by beating Serbia.

The 10m air rifle mixed team bronze and gold medal matches were taking place later on Tuesday.

AUSSIES SINGING IN MEN'S HOCKEY

World number two side Australia knocked off reigning Olympic gold medallists Argentina 5-2 in the men's hockey group stage.

Australia claimed their third consecutive victory and top Group A, this time being aided by two goals from Blake Govers.

The Kookaburras have only won one Olympic gold despite often being a dominant side in men's hockey and are one of the favourites to triumph in Tokyo.

Japan and New Zealand, who both previously lost to Australia, drew 2-2 in the other Group A game.

In Group B, world number four India won 3-0 over Spain, while fifth-ranked Germany beat Great Britain 5-1.

Naomi Osaka saw her Olympic gold medal dream shattered by a third-round defeat to Marketa Vondrousova at Tokyo 2020 on Tuesday.

Osaka lit the Olympic cauldron on Friday and was widely hailed as the 'face of the Games', with enormous expectation that she would go on to triumph for hosts Japan.

The early exit of world number one Ash Barty seemed to help her case, but Osaka lost 6-1 6-4 to her Czech opponent in an hour and eight minutes.

South African eighth-seed Lloyd Harris was bundled out by Australian Jordan Thompson 7-6 (7-2) 1-6 6-2 in a seesawing contest.

Thompson, who is ranked 63rd in the world, got the better of Harris, showing to grit to win in two hours and 30 minutes.

In the final match of the day, play was suspended due to rain and lightning after the first set with American Sam Querrey leading 6-4 against German Peter Gojowczyk.

Former world number 11 Querrey sent down 12 aces in the first set before the weather intervened.

The winner of Querrey and Gojowczyk will take on Thompson.

Steve Johnson defeated Alexei Popyrin 7-6 (7-4) 6-3, while Bjorn Fratangelo beat Italian Andreas Seppi 7-5 7-6 (7-5).

Pedro Martinez outlasted Lucas Pouille to set up a second-round clash with fellow Spaniard Roberto Bautista Agut at the Generali Open.

World number 97 Martinez came through Monday's longest match, which lasted two hours and 43 minutes, as a 6-3 6-7 (4-7) 6-4 winner.

Mikael Ymer, who reached the quarter-finals of last week's Swiss Open Gstaad, is also through to the second round in Austria after battling past Pablo Cuevas 6-3 7-5.

Qualifier Jozef Kovalik will face Jiri Vesely for a place in the quarter-finals, meanwhile, after beating ninth seed Jaume Munar in straight sets.

Also through on Monday was lucky loser Carlos Taberner, who took advantage of his second chance by battling from a set down to overcome Thiago Seyboth Wild 3-6 6-3 6-2.

The Tokyo Olympics are now in full swing and there are another 22 gold medal events to come on an action-packed Tuesday at the Games.

Plenty of focus will be on the Tokyo Aquatics Centre once again, where four medals are on the line, while the women's triathlon will also take centre stage.

Simone Biles, Naomi Osaka and Katie Ledecky are just some of the superstar names that will be in action on the fourth full day of the 2020 Games.

Stats Perform picks out of some of the standout action to look out for.

CAN BILES PUT BLUNDERS BEHIND HER?

Biles struggled to find top gear in her Games entrance on Sunday, albeit making it through to each of her finals, and there is no room for any slip-ups in the women's team final.

The Russian Olympic Committee finished above the United States at a major event for the first time since 2010 in qualifying, setting up an intriguing battle in the final.

The pressure is on Suni Lee, Jordan Chiles, Grace McCallum and indeed Biles, the latter of whom is aiming to add to the four golds won in Rio five years ago.

USA-JAPAN MEET IN SOFTBALL FINAL

Team USA's women's softball team recovered from behind to beat Japan 2-1 in their final round-robin game and finish top of the standings.

Japan finished second and the two sides are therefore set to face off in a huge gold medal match at Yokohama Baseball Stadium.

Mexico and Canada meet in the bronze medal contest earlier on Tuesday in a tasty warm-up match for the main event.

LEDECKY AND TITMUS RESUME RIVALRY

After winning four golds in Rio five years ago, Ledecky had the chance to add four more to her collection in Tokyo.

She fell short in the first of those events, however, with Australia's Ariarne Titmus taking gold in Monday's gripping 400m freestyle final.

While a medal is not on the line on Tuesday, Ledecky will be eager to lay down a faster time than her rival in the 200m freestyle heats ahead of Wednesday's showpiece.

OSAKA GOES AGAIN

Face of the Games Okaka followed up lighting the Olympic cauldron on Friday with victories over Zheng Saisai and Viktorija Golubic in her first two matches in the tournament.

The four-time grand slam winner has a quick turnaround in matches as world number 41 Marketa Vondrousova awaits in the third round on Tuesday.

Fellow home favourite Kei Nishikori is also in action in the men's event, with Marcos Giron standing between him and the last 16.

WOMEN'S TRIATHLON TOUGH TO CALL

There was drama before the men's triathlon had even officially got underway on Monday, with an inflatable boat carrying photographers causing a false start.

Norway's Kristian Blummenfelt won the competition and now it is over to the women, with 54 athletes in contention to claim gold.

The field is wide open this time around, though the likes of Katie Zaferes and Georgia Taylor-Brown, of Team USA and Great Britain respectively, will have their eyes on the top prize.

World number one Novak Djokovic made light work of Jan-Lennard Struff to continue his progress at the Olympic Games, and he revealed he is thriving off the energy in Tokyo as he copes with the weight of expectation.

Djokovic is aiming to complete a Golden Slam this year, having already swept up the Australian Open, French Open and Wimbledon titles.

Olympic gold is next on his list, before the Serbian will head to the US Open.

Struff was no match for the 34-year-old on Monday, as he teed up a round-of-16 tie with Alejandro Davidovich Fokina by beating the German 6-4 6-3.

Djokovic will be joined by fellow favourites Alexander Zverev and Daniil Medvedev, as the singles competition begins to hot up.

DJOKOVIC THRIVING IN TOKYO

Djokovic is aiming to become the first man in the Open Era to complete a Golden Slam, though even if he did not have such a feat in his sights, he would still have the expectation of clinching gold, given Roger Federer and Rafael Nadal chose not to compete.

"I think that once you reach the top spots of the rankings and start winning slams, you're going to experience different kinds of expectations and pressure from yourself and from people around," Djokovic said.

"It's kind of a normal thing that a lot of athletes from our sport have been experiencing in the past and it's going to happen in the future."

The 20-time grand slam champion also revealed he is splitting his time between a hotel and the Olympic athletes' village, as he looks to soak up the atmosphere in Tokyo, despite the ongoing coronavirus restrictions.

"I only stayed in the Olympic village the first few days in Rio, then I moved when the competition started to the hotel," he explained.

"Here, I'm between the hotel and the village but I'm spending every single day in the village mostly and the hotel is mostly for sleeping over, basically, and having my own routine in the morning.

"Other than that, I'm always in the village because it's just so special. Most of the tournaments I'm in a hotel anyway and this [Olympic Games] happens once in four years. Of course, I try to balance things out with keeping my own routines and things that make me feel good, but I'm thriving also on that wonderful energy in the village."

SPIDERCAM FACES ZVEREV'S WRATH

Alexander Zverev moved confidently into the round of 16, defeating Colombia's Daniel Elahi Galan Riveros 6-2 6-2 in just 71 minutes.

In fact, his greatest nemesis was the spidercam, which came a little too close for the German's comfort.

Zverev clipped a ball at the camera suspended above his head as he prepared to serve – the world number five claiming he almost hit the wire holding the device in place when he threw the ball.

"It was three meters above me, I almost hit the wire rope when I was throwing the ball. It just hung too low," he said, though the chair umpire disagreed.

There was ultimately no negative impact on Zverev's performance, and the 24-year-old will face Georgia's Nikoloz Basilashvili for a place in the last eight.

Basilashvili got the better of Italian world number 26 Lorenzo Sonego 6-4 3-6 6-4 to secure his progression.

MEDVEDEV MAKES HIS CLASS COUNT

The gulf in quality between Daniil Medvedev and Sumit Nagal of India was clear to see, as the world number two – who is representing the Russian Olympic Committee – cruised through in just 66 minutes.

Nagal, ranked 160th in the world, dropped serve in the first game of the match and never looked likely to recover, and the Australian Open runner-up breezed into the next round 6-2 6-1.

Medvedev will next go up against Italy's Fabio Fognini. The Russian has faced the world number 31 on four occasions, winning three times.

MURRAY (NO, NOT THAT ONE) DROPS OUT

Great Britain's Olympic team had a day to remember on Monday, but Jamie Murray and his doubles partner Neal Skupski could not carry on their run.

Kei Nishikori and Ben McLachlan, representing hosts Japan, got the better of the British duo 6-3 6-4.

Murray – whose brother Andy is also competing in the doubles but has withdrawn from the singles, in which he was defending champion – was called up as a late replacement for Dan Evans.

He has not made it past the second round in four Olympic Games, despite having won seven grand slam doubles titles.