WIMBLEDON, England — 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 today as the All England Club enjoyed a second spell of dry, sunny weather on a day that also featured wins by Rafael Nadal and Andy Roddick and former champions Maria Sharapova and Lindsay Davenport. Fourth-seeded Nikolay Davydenko was the top name to go out.

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 (201 kph). "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 a win at Queen's for his first grass-court title — got off to a solid start on Centre Court. Runner-up to Roger Federer the past 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."

Two-time runner-up Andy Roddick served 17 aces and never faced a break point as he downed Eduardo Schwank of Argentina 7-5, 6-4, 7-6 (0). The sixth-seeded Roddick, who lost to Federer in the 2004 and '05 finals, had only nine unforced errors. That compared with 21 for Schwank, who was making his Wimbledon debut and received a warning from the umpire after cracking his racket on the turf following the second set.

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. It was the fifth time in seven years the Russian failed to get past the first round; he reached the fourth round last year.

"He played good, but I played very bad," Davydenko said.

The Russian player 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 Tuesday, 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.

Wimbledon lost the oldest player in the men's draw, 36-year-old Jonas Bjorkman, when he lost 4-6, 7-6 (4), 6-4, 7-6 (4) to Arnaud Clement. It was the Swede's 15th and last Wimbledon before his planned retirement in October.

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.

"I'm very inspired by menswear this year," Sharapova said. "Every year at Wimbledon I want to do something classy. I've never worn shorts before at a Grand Slam and Wimbledon is the place to do it."

Davenport, the 1999 champion competing in her 13th Wimbledon at age 32, overcame a leg injury to beat Renata Voracova 6-3, 5-7, 6-3. Davenport missed the tournament last year after giving birth to a son in June 2007.

Davenport, who squandered a match point in the 10th game of the second set, took an injury timeout before the third. A trainer strapped her right leg from mid-calf to thigh. Davenport limped through the third set, going for big shots, and managed to win. After match point, she looked to the sky and limped off the court without a smile.

Cavaday, a left-hander with a world ranking of No. 197, pushed Williams to the limit in a surprisingly tough opening set that lasted nearly an hour.

With nothing to lose, Cavaday went for her shots and got out to leads of 2-0 and 3-1. She missed a chance to go up 4-2 and Williams rallied to go ahead 4-3.

Cavaday, however, didn't wilt and forced a tiebreaker. Williams was up 3-1 and 4-2 in the tiebreaker, but Cavaday got back to 4-4 with a forehand winner. At 6-4, Williams squandered a set point with a forehand error. She converted on the second when Cavaday couldn't handle a second serve and sent a forehand return into the net.

Cavaday held to open the second set, but Williams then reeled off six straight games to close out the match, and celebrated with twirls to the crowd.

Among those in the stands were her mother, Oracene, and sister Serena, the two-time champion who won her first-round match Monday. The Williams sisters, who could meet in the final, have won six of the last eight Wimbledon titles.