Rafael Nadal has bowed out of the French Open in the first round, beaten by Alexander Zverev, and admitted there is a "big percentage" chance it is his last match at the event he won 14 times.
However the King of Clay said he intended to return to Roland Garros for the Olympics in July.
Nadal lost 6-3 7-6 (7-5) 6-3 but the match against the No.4 seed was closer than the scoreline suggests with Nadal, 38 next week, battling hard for three hours.
It was the Spaniard's fourth Roland Garros defeat in 116 matches.
"The feelings I have are difficult to describe in words. It is difficult for me to talk. Honestly I don't know if it will be the last time before you all," the 14-time champion said.
"It is a big percentage I will not be back, but the body is feeling a bit better and I having fun. Maybe in two months I will say enough, but I hope to be back on this court in two months for the Olympics. That motivates me."
Nadal was broken by in-form Rome champion Zverev in the opening game and surrendered his serve again late on to drop the first set in unfavourable conditions for him with the roof closed due to heavy rain.
In the second Nadal broke for the first time with a delicate drop and took a 4-2 lead with some vintage shots on both flanks, but Zverev broke back when Nadal served for the set. He then edged a high-octane tiebreak.
Watched on by his great rival Novak Djokovic and a host of other current players, Nadal surged to a 2-0 lead in the third set but squandered it as Zverev drew level and dealt another body blow in the seventh game before serving out.
Earlier Italian world No.2 Jannik Sinner looked fully recovered from his injury problems as he saw off American Christopher Eubanks 6-3 6-3 6-4.
Sinner, the Australian Open champion, withdrew from the Madrid Open and missed the Rome Masters with a hip injury, but was back on form at Roland Garros on Monday as Eubanks exited at the first hurdle for the second straight year.
"The hip is good, I'm glad that my team and myself, we were working very hard to be on court as soon as possible," Sinner said.
"For sure, the general shape is not at 100% yet, so we try to build every day."
Sinner, who can become world No.1 for the first time over the next fortnight, will next play French wildcard Richard Gasquet, with the Italian hoping to avoid a repeat of last year when he went out in the second round.
Fifth-seeded Russian Daniil Medvedev, who was bundled out at the first time of asking last year, recorded a 6-3 6-4 5-7 6-3 triumph over Dominik Koepfer of Germany and will next face Serbia's Miomir Kecmanovic.
Former runner-up Stefanos Tsitsipas kicked off his campaign with a no-nonsense 7-6 (9-7) 6-4 6-1 victory over Marton Fucsovics. The ninth-seeded Greek, who won the Monte Carlos Masters this year, set up a second-round meeting with German Daniel Altmaier.
Russia's Pavel Kotov upset British 32nd seed Cameron Norrie 4-6 6-3 3-6 7-6 (7-5) 6-2 and set up a clash against former French Open champion Stan Wawrinka in the second round.
French 29th seed Arthur Fils was surprised by Italy's Matteo Arnaldi but seeds Karen Khachanov (8), Tommy Paul (14), Ben Shelton (15), Sebastian Baez (20), Felix Auger-Aliassime (21), Francisco Cerundolo (23) and Lorenzo Musetti (30) all progressed.
