Roger Federer could be excused if he has a restless night.

With thick gray clouds overhead and light slipping away at the end of a rainy day, Federer got broken by Gael Monfils to even their French Open fourth-round match at a set apiece, right before play was suspended Sunday.

They met on the sideline to chat with the chair umpire, then clasped hands, and Monfils gave Federer a playful pat on the shoulder. Spectators at Court Philippe Chatrier booed and whistled upon hearing there'd be no more tennis.

Federer, the 17-time Grand Slam champion, and Monfils, the flamboyant Frenchman who won their two most recent encounters, will resume Monday. At least they finished two sets, with Federer taking the first 6-3, and Monfils winning the second 6-4.

Two women's matches did not begin at all Sunday, including defending champion Maria Sharapova against Lucie Safarova.

In the quarterfinals, Federer or Monfils will face Federer's Swiss Davis Cup teammate Stan Wawrinka, seeded eighth, who had no trouble beating 12th-seeded Frenchman Gilles Simon 6-1, 6-4, 6-2.

Wawrinka said he'll be watching the rest of Federer-Monfils "like any tennis fan."

On the other half of the draw, No. 5 Kei Nishikori became the first Japanese man in 82 years to reach the quarterfinals in Paris, eliminating Teymuraz Gabashvili 6-3, 6-4, 6-2.

"I hope it's just the start of my journey and I hope I can keep going," said Nishikori, who had three days off because his third-round opponent withdrew with an injury.

The only other man from his country to make it this far at this tournament was Jiro Satoh, a semifinalist in 1931 and 1933.

Next for Nishikori is No. 14 Jo-Wilfried Tsonga of France, who overcame a mid-match lapse to defeat No. 4 Tomas Berdych 6-3, 6-2, 6-7 (5), 6-3.

Tsonga, the 2008 Australian Open runner-up, served for the match at 5-4 in the third set but got broken, and his sloppy play carried into the tiebreaker.

"I had a little bit of a dip, when I fell back into my bad, old ways," Tsonga said. "I've been working a lot with my coaches to limit that."

Had he managed to close things out earlier, or if a rain delay of about 2 1/2 hours hadn't interrupted action in the afternoon, Federer and Monfils might have finished. They didn't get on court until after 7 p.m. and competed for less than 70 minutes.

With the temperature in the low 60s (teens Celsius), Monfils covered up with a blanket and blew his nose into a tissue during a changeover. As natural light disappeared — there are no artificial lights at Roland Garros, and a roof won't arrive before 2019 — the chair umpire reminded fans they shouldn't use a flash while taking photos during points.

Monfils got broken while serving for the second set at 5-3, and Federer — who lost in the fourth round last year — had an opening to perhaps steal a two-set lead. But Monfils responded in the next game, winning an 18-stroke exchange with a forehand to earn to set point, then converting with a backhand that drew roars from the crowd.

Monfils leaped, yelled "Allez!" and waved both arms to ask for more noise.

Moments later, everyone was sent home, setting up quite a schedule Monday. Along with Federer-Monfils and Sharapova-Safarova, there will be matches featuring Rafael Nadal, Novak Djokovic, Andy Murray and Serena Williams.

In a women's match Sunday, No. 7 Ana Ivanovic beat No. 9 Ekaterina Makarova 7-5, 3-6, 6-1 to return to the quarterfinals for the first time since winning the 2008 title.

"On the one hand, it does feel like it's a different life. On the other hand, I feel like time is really flying. I feel it hasn't been that many years," said Ivanovic, who briefly was ranked No. 1 after winning her lone Grand Slam trophy. "I definitely do have the feeling it's amazing."

Her match was halted by rain after five games, and tournament officials wavered about when to resume.

"It was like, 'OK, in half an hour. In half an hour. In half an hour.' So it was really not easy to relax and refocus," Ivanovic said. "I was really happy I managed to keep composed."

She'll play No. 19 Elina Svitolina, a 23-year-old from Ukraine who reached her first major quarterfinal with a 6-2, 7-6 (9) victory over No. 29 Alize Cornet.

In the second set, Cornet berated the chair umpire over a line call, daring her to "give me a warning" and saying the official "stole" a point. Later, Cornet referred to the ruling as "a shame" and "a scandal."