Nadal matched world number four Zverev for long periods on a packed Court Philippe Chatrier, but slipped to a 6-3, 7-6 (7/5), 6-3 loss as he was beaten for just the fourth time in 116 matches at the tournament.

This year's event was expected to be the 14-time champion's farewell to Roland Garros, but he had since insisted he could not confirm "100 percent" it would be his last appearance.

"If it is (the last time), then you have been amazing. The feelings I have today are difficult to describe in words. It is the place I love the most." Nadal told an adoring crowd under the Chatrier roof.

Nadal, who turns 38 next week, showed all his trademark fighting qualities in a gripping match, but only managed to convert two of 11 break points against an inspired opponent.

"The first round wasn't ideal," he admitted, before saying he "hoped" to be back at Roland Garros later this summer for the Paris Olympics but would almost certainly skip Wimbledon. "It will be difficult playing on grass considering that right after Wimbledon are the Olympic Games."

It was only Nadal's fifth tournament since January 2023 after suffering a hip injury and then a muscle tear, arriving in Paris a lowly 275th in the world rankings.

"It's hard to say about the future," he added. "I am travelling with my family and I am having fun. The body is feeling better than it did two months ago."

Nadal was unseeded for the draw and vulnerable to a difficult opening round.

German Zverev, who lifted the Rome Open title last month, proved too strong despite the fans desperately attempting to raise Nadal to past glories. The 27-year-old banished the memories of the duo's last meeting, when he left Chatrier court on a wheelchair after injuring his ankle during their 2022 French Open semi-final. His reward for becoming just the third player to defeat Nadal at Roland Garros —after Novak Djokovic and Robin Soderling— is a match against either David Goffin or home wildcard Giovanni Mpetshi Perricard.

Zverev's fast start 

Zverev started the match strongly with a break to love in the opening game, going on to wrap up the first set with relative ease. Nadal was much improved from his most recent outing, when he was well beaten by Hubert Hurkacz in the Rome second round, but failed to serve out the second set when leading 5-4.

Zverev then came out on top in a tense tie-break as a Nadal return found the net. The Spaniard again broke first in the third set to lead 2-0, much to the delight of the 15,000 spectators in attendance, including Djokovic, Carlos Alcaraz, Swiatek and Manchester City footballer Rodri.

But Zverev quickly hit back once more, before breaking for a 4-3 lead with a wonderful passing winner. He secured victory on his first match point as Nadal blazed a forehand off target, potentially ending the most dominant career at a single event in Grand Slam history.

Swiatek makes strong start 

Women's world number one Iga Swiatek raced to a 6-1, 6-2 victory against French qualifier Leolia Jeanjean after just 61 minutes on Court Philippe Chatrier. The Pole will next face fellow four-time major champion Naomi Osaka on Wednesday.

"I'm really happy to be back. Feel like I'm playing really good tennis so hoping to be here as long as possible," said Swiatek.

The 22-year-old is aiming to become the first woman to win three straight Roland Garros titles since Justine Henin in 2007, and only the second ever after Serena Williams to win the Madrid, Rome and French Opens in the same year.