WIMBLEDON, England - On one point Tuesday at Wimbledon, Serena Williams dumped a forehand into the net and dropped to a knee, her jaw clenched as she let out a shriek.

On another, she pushed a backhand into the net while her feet gave way, yet again leaving her awkwardly splayed on the grass at Court 2, the same place where her sister Venus lost a day earlier.

By the end, the younger Williams was screaming after nearly every point, good or bad - and, well, there were plenty of both. Her harder-than-the-score-looked 6-2, 6-4 victory over the 62nd-ranked Barbora Zahlavova Strycova of the Czech Republic in the first round at the All England Club wasn't exactly perfect or pretty.

"Definitely a little relief," the sixth-seeded Williams said. "I was letting out a lot of cries. I was happy to get through that."

Two-time Wimbledon champion Rafael Nadal, for instance, trailed 4-0 against 80th-ranked Thomas Bellucci of Brazil before turning it around and winning 7-6 (0), 6-2, 6-3.

Defending women's champion Petra Kvitova fell behind 3-0 and 4-1 but eventually used a seven-game run to take control and beat 96th-ranked Akgul Amanmuradova 6-4, 6-4. The match was halted by a 30-minute rain delay in the second set; when they returned, Kvitova needed all of three minutes to wrap things up.

"In the beginning," Kvitova acknowledged, "I think I was nervous."

Twelve singles matches were suspended in progress and four were postponed altogether due to rain. Among those that began but didn't finish, 2003 U.S. Open champion and three-time Wimbledon runner-up Andy Roddick led British wild-card entry Jamie Baker by a set and a break.