Nursing a sore shoulder, Jelena Jankovic won one point with broken strings, another after falling down and the last one despite blowing a big lead.
Ana Ivanovic had a much easier time, sweeping every game.
And when the tennis turned tense for Novak Djokovic, he defiantly pounded his chest and whacked winners.
In succession on center court, the three Serbs advanced this morning to the quarterfinals at the French Open.
The No. 3-seeded Jankovic twice received treatment on her shoulder, lost four consecutive games after reaching match point and still managed to beat No. 14 Agnieszka Radwanska 6-3, 7-6 (3).
"I managed somehow to win," Jankovic said.
The No. 2-seeded Ivanovic, runner-up at Roland Garros last year, returned to the quarterfinals with a 6-0, 6-0 victory over Petra Cetkovska.
"It was much tougher than it probably looked," Ivanovic said.
Djokovic twice overcame love-40 deficits to hold serve, banging his chest with his fist the second time, and beat No. 18 Paul Henri-Mathieu 6-4, 6-3, 6-4.
"There is a lot at stake," Djokovic said. "I just want to keep on going."
Seeded third, he'll next play 19-year-old Ernests Gulbis of Latvia, who reached his first Grand Slam quarterfinal by beating Michael Llodra 6-4, 7-6 (4), 6-3.
Three-time defending champion Rafael Nadal returned to the quarterfinals by beating fellow Spaniard Fernando Verdasco 6-1, 6-0, 6-2. It was Nadal's most lopsided victory yet at Roland Garros, where he's 25-0.
"I wish all my matches were like this one," Nadal said.
On Tuesday - his 22nd birthday - Nadal will play yet another Spaniard, No. 19 Nicolas Almagro, who beat Jeremy Chardy 7-6 (0), 7-6 (7), 7-5.
The two women who upset the Williams sisters Friday were eliminated in their next match. No. 27-seeded Katarina Srebotnik, who had beaten Serena Williams, lost to No. 10 Patty Schnyder 6-2, 6-4. No. 26 Flavia Pennetta, who ousted Venus Williams, lost to 19-year-old qualifier Carla Suarez Navarro 6-3, 6-2.
Jankovic and Ivanovic are one round from an all-Serb showdown in the semifinals. But health issues put Jankovic's prospects in doubt.
She blamed her shoulder pain on a recent bout of swelling in her right forearm.
"I think the other muscles are compensating, so the whole arm is a mess," Jankovic said.
Leading 2-1 in the second set, she called for treatment and winced as a trainer massaged her shoulder near her neck. Some of her shots lacked their usual punch thereafter, but Jankovic built a 5-2 lead thanks to some shaky play by Radwanska.
Serving in the next game, Jankovic reached match point three times but failed to hold, and Radwanska took advantage of the reprieve to mount a comeback.
"I made a lot harder work than it should be," Jankovic said.
She scrambled to stay in the set. At 5-5, she slipped and fell 10 feet behind the baseline, quickly rose to remain in the rally and won the point when Radwanska pushed a backhand wide.
In the next game, Jankovic floated a forehand winner cross-court after her strings popped, helping her to hold serve for 6-all.
Radwanska committed five unforced errors in the tiebreaker, including an errant backhand to end a 28-stroke rally on the final point. A relieved Jankovic looked to the sky and crossed herself.
"I didn't want to be here for the third set," she said, the back of her dressed still caked in clay from her spill. "I was struggling at the end. ... I was just trying to guide the ball with my arm, which was not enough."
The first match of the day on center court was a quite a contrast, and Ivanovic was finished shortly after noon.
"I played almost without mistake," she said.
A finalist at the Australian Open in January, Ivanovic lost the match's first two points, then proceeded to dominate. It was the second love-love result of the women's tournament, and Ivanovic's first such victory since May 2005.
She has yet to lose a set in four rounds.
"I was really happy the way I performed all these matches so far," she said. "I had fun out there today. I want to keep the hard work and keep grinding on the clay."
Cetkovska, ranked 77th, was playing in only her third Grand Slam tournament.
"I put too much pressure on me, and I tried to do too much," Cetkovska said. "But then, of course, she played very well."
Ivanovic only faced two break points, both while serving at 4-0 in the second set. On Tuesday, she'll next face Schnyder for a berth in the semifinals.
Jankovic will have a day to recuperate before she plays Suarez Navarro, the first qualifier to reach the women's quarterfinals at Roland Garros since Petra Mandula in 2001.
