LONDON – Dismayed at dropping the first set after being a single point from taking it, Serena Williams sat in her Centre Court sideline chair and cracked her racket against the turf once, twice, three times, four.

Then she casually flung the racket, hurling it so far behind her that it landed in the lap of a TV cameraman filming her second-round match against 65th-ranked American Christina McHale.

Williams recovered to force a third set, only to fall behind yet again Friday, perilously close to what would have been the six-time champion’s earliest exit in 17 Wimbledon appearances.

But as she herself declared afterward: “Mentally, no one can break me.”

Eventually, the top-ranked Williams did indeed come through, edging McHale 6-7 (7), 6-2, 6-4 for a thrill-a-minute victory at a tournament so rain drenched this week that matches will be scheduled on the middle Sunday for only the fourth time in 139 years.

The dramatics of Williams’ match, which concluded with the main stadium’s retractable roof closed, were equaled by those of her older sister Venus: She had to wait out three rain delays, including one of more than an hour that arrived, of all times, right as she held a match point. But Venus, owner of five titles at the All England Club, persevered, too, barely getting past 29th-seeded Daria Kasatkina 7-5, 4-6, 10-8 to become one of only two women already into the fourth round.

“You see a winner go by you, and a lob go in, and you’re like, ‘My god, what’s next?'” said Venus, who at 36 is the oldest woman in the field and has played about 61/2 hours of tennis in the past two days, including singles and doubles.

Of the way things went for her Friday, including the interruption at match point while she led 5-4 in the third and Kasatkina served at 30-40, Venus said: “It was like a Hollywood script.”

Despite all that went on in the siblings’ matches – they overlapped, so their mother, Oracene Price, hustled from No. 1 Court, where she saw Venus win, across the way to catch the end of Serena’s victory – the most shocking development Friday was what was going on in Novak Djokovic’s third-rounder against 28th-seeded Sam Querrey of the U.S. before it was suspended because of showers in the evening.

Djokovic, owner of a 30-match Grand Slam winning streak that includes the past four major titles, allowed Querrey to seize the first two sets 7-6 (6), 6-1 during their 72 minutes of action. Given the way things were going for the No. 1-seeded Djokovic, he had to be thrilled that the match was halted, giving him a night to rest and regroup.

Only one man managed to move his way into the fourth round: Roger Federer. He got to play in the main stadium, with the roof overhead, and easily beat Britain’s Daniel Evans 6-4, 6-2, 6-2.

Four other third-round men’s matches were suspended in progress. Worst of all, from a scheduling standpoint, one second-round men’s match is still not finished, with No. 24 Alexander Zverev locked in a fifth set against Mikhail Youzhny. And three second-round women’s matches are also pending.

That is why officials decided to scrap the traditional rest day on the first Sunday, something that was done only in 1991, 1997 and 2004.

“I might take a day off tomorrow, just because I can,” the 34-year-old Federer said with a smile. “Yeah, I can. I’m sorry, I can. I have to take them when I can. I’m an old guy.”

Among the other winners Friday was 2009 U.S. Open champion Juan Martin del Potro, who eliminated fourth-seeded Stan Wawrinka 3-6, 6-3, 7-6 (2), 6-3.