PARIS >> Serena Williams was ahead, yes, but hardly at her best, when claps of thunder and a heavy downpour interrupted her third-round French Open match at a critical juncture.
So during what turned out to be a delay of more than 21/2 hours right before a second-set tiebreaker Saturday against 26th-seeded Kristina Mladenovic of France, Williams met with coach Patrick Mouratoglou.
"I spoke 10 minutes, which is far too long. Actually, at the end, I said: 'Sorry. I spoke too long. Much too long.' Because a long speech is not a good speech; it has to be short and powerful," Mouratoglou recounted later. "My point was just to make her think the way she thinks when she's good, when she's playing like Serena plays."
Did it work?
"Just look at the score," Mouratoglou said, "and, more than that, look at the way she did it."
Coming out of the locker room determined to dictate play more than she had been, Williams edged Mladenovic 6-4, 7-6 (10), a victory that set up a fourth-round matchup against a woman whose coaching consultant is the 34-year-old American's former rival, Justine Henin.
"Up until that point, I had not been playing my game. I was playing really defensive. It's not me," said the top-seeded Williams, who compiled a 5-2 advantage in winners in the tiebreaker. "So I just wanted to be Serena out there."
Her sister Venus, seeded No. 9, beat France's Alize Cornet 7-6 (5), 1-6, 6-0 to reach the fourth round for the first time since 2010. And another American, No. 15 Madison Keys, got that far at Roland Garros for the first time with a 7-6 (3), 6-3 victory over Monica Puig.
Quarterfinal berths will be at stake in these matchups Monday: Venus vs. No. 8 Timea Bacsinszky, Keys vs. Kiki Bertens, No. 12 Carla Suarez Navarro vs. Yulia Putintseva.
Next up for Serena Williams is No. 18 Elina Svitolina of Ukraine, who was 0-7 against Ana Ivanovic before beating the 2008 French Open champion 6-4, 6-4.
Svitolina, 21 and the winner of the girls' title in Paris in 2010, is 0-3 against Williams. But the far more fascinating storyline involves Henin, a seven-time major champion whose playing career ended in 2011 and who has been helping Svitolina with the mental aspects of tennis for the past few months.
Williams and Henin played each other 14 times (Williams won eight, including the 2010 Australian Open final). Their most infamous encounter came at the 2003 French Open: There was a flap over whether Henin tried to call time; Williams drew fans' ire by arguing line calls; Henin's three-set victory ended a 33-match Grand Slam winning streak for Williams, who was jeered off the court, then teared up while talking about it all.
On Saturday, Williams deflected a question about what it might be like to see Henin in a foe's camp all these years later.
Trying to become the first woman to win consecutive titles at Roland Garros since Henin took three in a row from 2005-07, Williams knows she will have to do a better job of capitalizing on chances than she did against Mladenovic, 23, who called it a dream to finally get to play against someone she grew up watching on TV.
Williams went only 1 for 12 on break points and needed five — yes, five — match points in the tiebreaker to close things out, erasing a set point for Mladenovic along the way.
"Barely getting through that — I had opportunities to end it a lot sooner," Williams said, "and I didn't."
In men's action, No. 1 Novak Djokovic finished his 6-2, 6-3, 6-3 victory over Aljaz Bedene just before nightfall, while No. 6 Jo-Wilfried Tsonga quit after seven games against Ernests Gulbis because of an injured right leg. Other winners: No. 7 Tomas Berdych, No. 11 David Ferrer, No. 12 David Goffin, No. 13 Dominic Thiem and No. 14 Roberto Bautista Agut.
Thiem, 22, got past Alexander Zverev 6-7 (4), 6-3, 6-3, 6-3 to close in on his first Grand Slam quarterfinal.
While the draw set up a potential fourth-round match for Thiem against Rafael Nadal, the nine-time French Open champion's withdrawal Friday because of an injured left wrist means that a far less daunting opponent awaits.
Instead, Thiem faces 56th-ranked Marcel Granollers, who never has reached a major quarterfinal, either.
"Against Rafa, I'm the underdog," Thiem acknowledged. "Against Granollers, I'm probably the favorite."