WIMBLEDON, England — Serena Williams collapsed with a strained calf, screamed in pain and buried her face in the grass behind the baseline, her bid for a third Wimbledon title in jeopardy.

Nearly three hours later, following a timely rain delay, she hobbled gallantly into the quarterfinals by beating Daniela Hantuchova 6-2, 6-7 (2), 6-2.

When the rain came, Williams was a set up but trailing 4-2 in the second-set tiebreaker. She limped off the court without bothering to fetch her tennis bag.

Following a delay of nearly two hours, Williams returned to the court with both legs taped, wearing sweat pants to keep warm in the cool conditions. She lost the first five points but then began to move better and hit more aggressively, while Hantuchova was erratic, perhaps unnerved by the unusual circumstances.

Hantuchova shanked several shots down the stretch, including one in the rally where she lost serve to fall behind 4-2. Williams frequently punctuated points by screaming, "Come on!" On the final point, she whacked a confident backhand return that Hantuchova couldn't handle.

Williams looked to the still-threatening sky and blew a kiss in gratitude toward the weather. She'll play top-ranked Justine Henin in the quarterfinals.

Henin, seeking the only Grand Slam title she has yet to win, beat No. 15-seeded Patty Schnyder 6-2, 6-2.

Williams' sister, Venus, made it to the fourth round despite a performance so filled with errors she drew criticism from her father.

The three-time champion rallied past Akiko Morigami 6-2, 3-6, 7-5 in a match suspended Saturday. And she did it even though she faced 23 break points, double-faulted 14 times and trailed 5-3 in the third set.

Serena Williams' injury, described by the WTA Tour as a spasm-induced left calf strain, struck after Hantuchova hit a forehand winner for a 5-5, 30-15 lead in the set. Williams grabbed her calf, tapped it three times with her racket head and fell to the grass.

She remained down for seven minutes. While a trainer massaged the calf, Williams grimaced, then screamed in pain.

She kept playing for another 11 minutes, wiping away tears before one point while hitting shots weakly and walking stiffly in pursuit of the ball. But she managed to hold for 6-all, then won the last two points before the delay.

Some Centre Court fans cheered the interruption, pleased to see Williams rewarded for her valiant attempt to keep playing. She said she took advantage of the break to receive treatment with ice and massages, and drank a lot of liquids.

Serena's mother and coach, Oracene Price, said she advised her daughter to stop playing.