Defending champion Venus Williams scraped through a tight first set and then pulled away for a 7-6 (5), 6-1 victory over British teenager Naomi Cavaday to begin her bid for a fifth Wimbledon title.

As reigning champion, Williams was up first on "Ladies Day" on Centre Court as the All England Club enjoyed a second spell of dry, sunny weather on a day that also featured wins by Rafael Nadal and Maria Sharapova and an upset loss by Nikolay Davydenko.

It took a while for the seventh-seeded Williams, playing her first grass-court match of the season, to find her game and take command against a 19-year-old wild card entry playing only her third career Grand Slam match.

"She played a great match," said Williams, who hit one serve at 125 mph. "She put a lot of pace on the ball, forced a few errors by me. I felt confident throughout the match. I felt good out there. I always feel good on that court."

Nadal, coming off his fourth straight French Open championship and first grass-court title, got off to a solid start on Centre Court. Runner-up to Roger Federer the last two years, the second-seeded Spaniard beat 122nd-ranked German qualifier Andreas Beck 6-4, 6-4, 7-6 (0).

Nadal, who never faced a break point, managed to break Beck just twice out of nine chances. He saved his best for the tiebreaker, ripping a crosscourt forehand winner for 5-0, serving his 17th ace for 6-0 and forcing an error on match point with a backhand drop shot.

"The first match is always very difficult, but I played well in the last tiebreak," Nadal said. "I was a little bit nervous today. It was tough, but I have very nice memories from the last two years."

In the day's first major upset, fourth-seeded Davydenko was knocked out in the first round in straight sets by 116th-ranked German Benjamin Becker, 6-4, 6-4, 6-4. "He played good, but I played very bad," Davydenko said.

The Russian has been at the center of an investigation into suspicious betting patterns involving a match in Poland last year when he retired citing an injury in the third set against Argentina's Martin Vassallo Arguello.

"Nobody can prove anything," said Davydenko, who has repeatedly denied any wrongdoing. "I think there's no match-fixing in tennis."

Arguello won his first-round match yesterday, outlasting Ivo Minar, 6-4, 2-6, 2-6, 6-2, 6-2.

Also advancing among the men was No. 8 Richard Gasquet, who beat Mardy Fish 6-3, 6-4, 6-2.

Another Wimbledon women's champion, 2004 winner Sharapova, advanced to the second round with a 6-1, 6-4 win on Court 1 over 105th-ranked French qualifier Stephanie Foretz.

"It was great to get out there and get a feel for the court," the third-seeded Sharapova said. "It was my first match on grass this year and I did pretty well considering."

A day after Roger Federer wore a custom-made cardigan onto Centre Court and Serena Williams donned a thigh-length trench coat, Sharapova made a fashion statement of her own. She came on court wearing shorts and a specially designed white tuxedo-style top.