Soon enough, he was in a real rut, in danger of his earliest exit from a Grand Slam tournament in nine years.
Federer regrouped and restored order eventually, coming back from a two-sets-to-one deficit to beat 15th-seeded Gilles Simon of France 6-1, 4-6, 2-6, 6-2, 6-3 on Sunday in the fourth round to reach his 36th consecutive major quarterfinal.
“I didn’t hurt myself or anything,” Federer said afterward. “But maybe I did lose that touch of confidence.”
During a rare stretch of mid-match mediocrity from the owner of a record 17 Grand Slam championships — the 2009 French Open trophy is part of his collection — Federer lost 10 of 13 games, including the one in which he fell.
But Simon, a former member of the top 10, could not keep Federer down. Still, Federer acknowledged the need to “tidy up my play” before he faces another Frenchman, No. 6-seeded Jo-Wilfried Tsonga, in the quarterfinals.
Federer’s turnaround was not the biggest of the day. Not even close. That distinction belonged to 32nd-seeded Tommy Robredo of Spain, who is specializing in comebacks: He is the first man in 86 years to win three matches in a row after dropping the first two sets.
Robredo did it in the second round Wednesday. He did it in the third round Friday. And then he did it in the fourth round Sunday, defeating No. 11 Nicolas Almagro 6-7 (5), 3-6, 6-4, 6-4, 6-4. Robredo also was behind 4-1 in the third set, 4-2 in the fourth and 2-0 in the fifth.
“Nobody dreams of doing such things,” said Robredo, who dropped to his knees, leaned forward and wept after winning.
“I don’t know what adjective to use,” he said.
Robredo’s first French Open quarterfinal since 2009 — he missed the tournament in 2011 and 2012 because of left leg problems that required surgery — will be against another Spaniard, No. 4 David Ferrer, who eliminated No. 23 Kevin Anderson of South Africa 6-3, 6-1, 6-1.
Tsonga, the 2008 Australian Open runner-up, had little trouble getting past Viktor Troicki of Serbia 6-3, 6-3, 6-3. Tsonga is 3-9 for his career against Federer, but he did come back from a two-set hole to win their 2011 Wimbledon quarterfinal.
Did it pretty quickly, too, exhorting himself more than usual with fist-shaking and yells of “Come on!”