PARIS (Reuters) - First the Williams sisters ambushed two home favorites, then Jo Wilfried Tsonga's chances were shattered by injury as French hopes were battered at a stormy Roland Garros on Saturday.
Top seed Serena Williams contended with thunder, rain delays and an inspired Kristina Mladenovic roared on by a partisan crowd but it was all in day's work for the holder as she moved ominously into the second week.
The 34-year-old American needed all her experience and tenacity to survive a compelling second-set tiebreak and claim a 6-4 7-6(10) victory to set up a last-16 clash with Ukraine's Elina Svitolina who beat 2008 champion Ana Ivanovic 6-4 6-4.
Shortly afterwards Venus beat unseeded Alize Cornet 7-6(5) 1-6 6-0 to make the fourth round for the first time since 2010 -- keeping alive the possibility of the sisters' first French Open clash since they contested the 2002 final.
Twice semi-finalist Tsonga was expected to fly the home flag but retired with a groin injury when up 5-2 against Latvia's Ernests Gulbis, leaving Court Philippe Chatrier in tears.
It means of the 26 French players in the singles draws only Richard Gasquet is still standing -- the worst showing by the home nation since 2010 when Tsonga was the last man standing.
"It's of course a big disappointment. I was in a really good shape today," sixth seed Tsonga told reporters referring to his positive start to the match.
"It's just really difficult to accept that I'm not in the tournament any more."
Despite the rain which saw matches shifted to different courts the last-16 lineups are complete.
Men's top seed Novak Djokovic cut it fine though.
The Serb was never in any danger of losing to Britain's Aljaz Bedene but had to race through the points to win 6-2 6-3 6-3 before the light made the courts unplayable.
"I closed out two sets pretty well. Started the third great, the night show started, we played to the maximum extension of time," Djokovic, who decried the lack of floodlights, said.
His quest for a first French Open title continues on Monday against Roberto Bautista -- the Spanish 14th seed outclassing Croatian teenager Borna Coric 6-2 6-3 6-3.
Seventh-seeded Czech Tomas Berdych, 12th seed David Goffin of Belgium, Austria's fast-rising Dominic Thiem and ever-reliable Spaniard David Ferrer also progressed.
Thiem, the 13th seed, outmuscled German teenager Alexander Zverev in four sets and plays Marcel Granollers next, rather than more illustrious Spaniard Rafael Nadal who rocked the tournament on Friday when he withdrew with a wrist injury.
Madison Keys made it four U.S. women through to the fourth round when she beat Monica Puig 7-6(3) 6-3.
Spain's Carla Suarez Navarro, last year's semi-finalist Swiss Timea Bacsinszky and two unseeded players, Kazakh Yulia Putintseva and Kiki Bertens of the Netherlands, also won.
With Roger Federer crocked, twice women's champion Maria Sharapova banned pending the outcome of an anti-doping hearing, Nadal and Tsonga forced out and bad weather ever-present, it has not been a vintage French Open to date.
But at least three-times champion Serena upped the ante to repel a stirring challenge from Mladenovic.
Everything seemed under control as she took the opening set but, as the sky darkened and fat rain drops began splattering on the clay late in the second set, Williams seemed over-anxious to get the job done and get in the dry.
Mladenovic, though, stayed strong and forced a tiebreak just at the moment the heavens opened.
When the contest resumed 2-1/2 hours later Williams went 5-2 behind but recovered to lead 6-5, only to make a hash of an overhead on match point.
A second chance came and went as she clubbed an easy forehand long after pouncing on an airy Mladenovic drop shot that sat up begging.
Williams saved a set point with a swing volley before another match point came and went but she finally produced her victory roar when her opponent sent a forehand wide at 11-10.
"It was definitely a challenge for me," Williams said. "I had opportunities to end it a lot sooner and I didn't.
"That's something that I can try to (do) going forward."
Editing by Julien Pretot and Ken Ferris