Hours later, the man Nadal beat in last year's final and could meet in this year's semifinals, No. 1 Novak Djokovic, seemed vulnerable, too. Walking to his changeover chair at 4-3 in the third set of a 6-2, 6-2, 6-3 win against No. 26 Grigor Dimitrov, Djokovic stretched his right arm the one he has used to win six Grand Slam titles several times. He then was treated by a trainer, who applied ointment and gave Djokovic a massage near the shoulder.
Two games later, the match was done, Djokovic was into the fourth round, and he raised that arm in his typical victory celebration.
His mood would shift dramatically soon. When Djokovic left the court and went to the locker room, he was told that his first coach Jelena Gencic, 76, who began working with little Nole when he was 6 had died in Belgrade, Serbia, earlier Saturday. Djokovic issued a statement through the tournament saying that he would not be able to attend a post-match news conference.
"His team kept the news secret from him until after the match," ATP spokesman Nicola Arzani said. "He just broke down. ... He was very, very, very close to her."
As they approach each other in the draw, Nadal now meets No. 13 Kei Nishikori the first Japanese man in the fourth round of the French Open in 75 years while Djokovic faces No. 16 Philipp Kohlschreiber. The other matchups on that half of the bracket after a wild Saturday in Paris: No. 12 Tommy Haas against No. 29 Mikhail Youzhny, and No. 7 Richard Gasquet against No. 9 Stanislas Wawrinka.
Haas let a record 12 match points get away from him in the fourth set, then saved one in the fifth. He eventually pulled out a 7-5, 7-6 (4), 4-6, 6-7 (10), 10-8 victory over 19th-seeded John Isner, the last American man in the field and the player best known for winning a 70-68 fifth set at Wimbledon three years ago.
"These long matches seem to follow me," said Isner, whose last five Grand Slam appearances ended with losses in five-setters.
"In hindsight, probably would have been better to lose in straight sets," he added, "because I feel terrible right now."
In Nishikori's victory, his opponent, France's Benoit Paire, was assessed a point penalty for getting coached. The same thing happened to Marina Erakovic during her loss to No. 17 Sloane Stephens, one of four U.S. women into the fourth round.
That's the most since four also made it in 2004; five made it a year earlier. She's joined by 54th-ranked Jamie Hampton, who stunned 2011 Wimbledon champion Petra Kvitova 6-1, 7-6 (7); 67th-ranked Bethanie Mattek-Sands, who also won Saturday; and 15-time major champion Serena Williams, whose fourth-round match is Sunday.
Stephens gets the most intriguing matchup with a quarterfinal berth at stake, taking on defending champion Maria Sharapova on Monday.
Sharapova, who completed a career Grand Slam in Paris last year, dealt with eight double-faults against unseeded Zheng Jie before winning 6-1, 7-5.
She was most disappointed by a line call on one of those double-faults, which came on break point and created a 4-1 deficit in the second set. The chair umpire climbed down to check the mark in the clay but, Sharapova said, the wrong one.
And she said the French Open should join other Grand Slam tournaments in using a video replay system.
"The umpire did not recognize that the mark he pointed out was about a foot away from the actual mark. So that's a huge question mark, to begin with," she said. "Second of all, yes, all the other Grand Slams have (replay). And I know these types of situations, although much more rarely on the clay, happen. Why not? Why don't we have a system like this? I mean, is it a money concern? I don't think so."
Hampton next plays 2008 U.S. Open runner-up Jelena Jankovic, Mattek-Sands faces No. 12 Maria Kirilenko, and 2010 champion Francesca Schiavone plays two-time Australian Open winner Victoria Azarenka.
Those matches will be Monday, when Nadal will return to the court, too. The way he's been playing, he looked forward to a chance to work on some things in the meantime.
Asked after the Fognini match what he's pleased with about his game at the moment, Nadal replied: "Not one."
He is trying to become the first man to win eight championships at one Grand Slam tournament and is now 55-1 at Roland Garros.
But, wearing a wrap of white tape below his oft-troublesome left knee, he was as erratic as ever Saturday, with 40 unforced errors and problems converting break points. He's never lost to a player seeded as low as Fognini at any major tournament but fell behind 3-2 when broken in the first set; perhaps coincidentally, Nadal was warned for taking too much time between points in that game. Nadal broke back, but later dropped serve again to trail 6-5.
In one stretch of that set, Nadal lost 10 of 11 points that lasted at least 10 strokes, the types of exchanges he typically controls.
If Fognini had not made as many errors as he did a botched overhead here, a sitter into the net there Nadal would have been in serious trouble. The Spaniard lost the first set against 59th-ranked Daniel Brands in the first round, and the first set against 35th-ranked Martin Klizan in the second round.
Nadal managed to pull out the first set in a tiebreaker against Fognini, but only allowed a smile to crease his face after 2 hours, 45 minutes of sneering while waving to the crowd when the match was over.
"If I can calm down, I will play better," Nadal said afterward. "Otherwise, I can go back to Mallorca and go fishing."
R Rafael Nadal and Novak Djokovic both reach the fourth round, as does American Sloane Stephens.