Reigning US Open champion and two-time French Open finalist Dominic Thiem squandered a two-set lead and is out of Roland Garros.
The fourth-seeded Austrian was beaten 4-6, 5-7, 6-3, 6-4, 6-4 by 68th-ranked Pablo Andujar in the first round, marking the first time in eight appearances at the clay-court Grand Slam that Thiem lost his opening match.
Andujar also defeated Roger Federer in Geneva earlier this month. It's the first time in his career that Andujar has come back to win after losing the opening two sets.
Thiem, who lost the 2018 and 2019 finals to Rafael Nadal, dropped to 11-9 in five-set matches.
One man who could take advantage of the lopsided nature of the bracket is No. 6 seed Alexander Zverev, the runner-up to Thiem at Flushing Meadows in September. Zverev did not look ready to contend for much of anything Sunday, however, needing a comeback of his own from two sets down to get past 152nd-ranked qualifier Oscar Otte 3-6, 3-6, 6-2, 6-2, 6-0.
Zverev acknowledged he stepped on court Sunday aware -- maybe too aware -- of his good friend Thiem's surprising loss.
"You try to focus on yourself. You try to not pay too much attention," Zverev said. "But you do know the draw. You know who is where. You know that Dominic is one of the best clay-court players, especially here, one of the toughest opponents you can have. And then he's out.
"It does affect you a little bit. Maybe that was part of the reason why I was a little bit nervous in the beginning."
Another former US Open finalist also had a hard time Sunday, but Kei Nishikori was able to prevail in his customary five sets.
Nishikori notched a 6-4, 6-7 (4), 6-3, 4-6, 6-4 win over Italian qualifier Alessandro Giannessi in the first round of the French Open. It was his 10th win in his past 11 five-setters; he is now 25-7 for his career.
"I have to figure it out, how to win in three sets," Nishikori said. "It's really hard to win like this."
Information from The Associated Press was used in this report.