Rafael Nadal began his bid for a record-setting 21st Grand Slam title with a straight sets win at the French Open on Tuesday as the fallout from Naomi Osaka's revelations over depression and anxiety sent shockwaves through Roland Garros.

Nadal, the 13-time champion in Paris, defeated 63rd-ranked Alexei Popyrin of Australia 6-3, 6-2, 7-6 (7/3) to take his record at the tournament to 101 wins against just two losses.

"I was lucky to win that third set, I don't know how (I did). The beginning of the match had been very tough too," said Nadal, who had been 2-5 down in the third set, saving two set points.

"In these warm and fast conditions it's always very difficult. He's young and the speed of his ball is very strong."

Up next is fellow 34-year-old Richard Gasquet.

Kvitova saved a match point in her first-round win
Kvitova saved a match point in her first-round win AFP / Christophe ARCHAMBAULT

The pair first played one another when they were children. As professionals, Nadal leads 16-0.

The Spaniard's opening win shifted the emphasis onto world number one, and potential semi-final opponent, Novak Djokovic who is chasing a second French Open title and 19th Grand Slam.

Djokovic was taking on 66th-ranked Tennys Sandgren of the United States in an evening session match-up.

World number one Ashleigh Barty marked her return to Paris for the first time since her 2019 title triumph by beating American left-hander Bernarda Pera 6-4, 3-6, 6-2 but admitted she was fighting a hip problem.

Barty, 25, skipped the defence of her title in 2020 due to the pandemic but this year has won trophies at the Yarra Valley Classic, Miami and on clay in Stuttgart in the run-up to Roland Garros.

Champion's style: Rafael Nadal serves to Alexei Popyrin
Champion's style: Rafael Nadal serves to Alexei Popyrin AFP / Christophe ARCHAMBAULT

After easing through the first set on Court Philippe Chatrier, Barty went off the boil in the second and called for the trainer at the changeover.

"I'm not going to hide behind the fact I'm not quite 100%," said Barty whose left thigh was heavily strapped.

"But I can guarantee that I will go out there with the right attitude every day and be really accepting of that and give it a crack no matter what."

Meanwhile, the fallout from Osaka's withdrawal continued to be felt.

The 23-year-old world number two, and four-time major winner, pulled out on Monday after she was fined $15,000 and threatened with disqualification for refusing to attend press conferences.

Power-packed: Australia's Ashleigh Barty returns the ball to Bernarda Pera
Power-packed: Australia's Ashleigh Barty returns the ball to Bernarda Pera AFP / Christophe ARCHAMBAULT

Osaka claims traditional post-match media conferences are akin to "kicking people when they're down" and were having a detrimental effect on her mental health.

She revealed she had been suffering bouts of depression since her 2018 US Open title breakthrough as well as anxiety attacks.

Her decision attracted widespread sympathy and accusations over the role of the media in the affair.

"There's a sense of voyeurism around how it presently works," wrote Peter Terry, a professor of psychology at the University of Southern Queensland in Australia on theconversation.com.

"Perhaps some want to see athletes crumble and break down into tears, having put them on a pedestal.

"Osaka is a young, introverted, anxious person. We should by now understand that sports stars are not super human, that they have the same doubts and mental health issues as everyone else."

Ironically, another Roland Garros press conference led Tuesday to the injury-enforced withdrawal of two-time Wimbledon champion Petra Kvitova.

The Czech 11th seed, a Roland Garros semi-finalist in 2012 and 2020, had saved a match point in her first-round win over Belgian qualifier Greet Minnen on Sunday.

"During my post-match press requirements on Sunday I fell and hurt my ankle. Unfortunately, after an MRI and much discussion with my team, I have made the tough decision that it would be unwise to play on it," said the 31-year-old.

Fifth seed Elina Svitolina, a three-time quarter-finalist, recovered from a 2-5 second set deficit to beat French teenager Oceane Babel 6-2, 7-5.

Italian 37-year-old Andreas Seppi, playing in his 63rd successive Grand Slam, stunned 20th seeded Felix Auger-Aliassime 6-3, 7-6 (10/8), 4-6, 6-4.

For Seppi, it was a first win at any level this year.

Venus Williams, playing the tournament for the 24th time and a runner-up 19 years ago, saw her 89th Grand Slam end at the first hurdle as Russia's Ekaterina Alexandrova eased to a 6-3, 6-1 win over the 40-year-old American.