WIMBLEDON, England -- Venus Williams opened her bid for a third straight Wimbledon title Tuesday with a routine Centre Court victory over a British wild card playing her first tour-level match.

The top-seeded American, aiming to become the first woman to win Wimbledon three years in a row since Steffi Graf in 1991-93, beat 344th-ranked Jane O'Donoghue 6-1, 6-1 in 44 minutes.

O'Donoghue, 19, came into the match as a 200-1 long shot with British bookmakers. She put up a gutsy performance but was never in the same league with Williams, who has won four Grand Slams and is the hardest hitter in the women's game.

"It was like David vs. Goliath in skirts,'' ESPN analyst Pam Shriver said on the BBC.

When O'Donoghue won her first game after going down 3-0 in the first set, she pumped her fists and tried to fire up the crowd. But Williams reasserted her authority with a huge serve on the next point and wrapped up the first set in 21 minutes.

Williams won 20 of 21 points on serve in the opening set. But she had trouble with her first serve and was broken by O'Donoghue in the third game of the second set. It was just a minor blip, though, as Williams sailed the rest of the way.

When it was over, Williams broke into her only smile of the match, beaming to the crowd as she did a little twirl.

Watching in the guest box alongside British heavyweight champion Lennox Lewis was Serena Williams, who is seeded to face her sister in the final.

As defending women's champion, Williams had the honor of opening Centre Court play Tuesday. But she said it wasn't the same as coming out the first time to defend her title.

``Last year, it was a really nice feeling, that's for sure,'' she said. ``When I came out this time, I was all business. I wasn't thinking about nostalgia or anything at all, except hitting the ball well.

``Afterwards, when I walked off, that's when I kind of realized, `I'm coming back as the defending champion. I have the honor to play first on.'''

Williams gave O'Donoghue credit but questioned why she stood in so close while returning serve. Williams won 18 of the 19 points in which she got her first serve in.

``Maybe she's never played a server like me before,'' she said with understatement. ``Actually, to be honest, she played very well. She executed quite well. But then I'm so comfortable on the grass. I served and returned well. I just have a lot more experience.''

O'Donoghue said the reality of the occasion hit her as soon as Williams came out and hit four big serves in the opening game.

``Then I realized, `I've got a mountain to climb here,''' she said. ``I felt I did do myself justice. I'm playing against the best player in the world. I thought I did quite well. I went out there and I enjoyed every minute of it.''

One of the women hoping to stop Venus's march toward the final, fifth seeded Kim Clijsters, had a stuttering start to her campaign.

Clijsters, seeded five to match her world ranking, was hardly out of first gear in the first set. She broke American Samantha Reeves in the third and seventh game and then taking the set with an ace.

Reeves, ranked 72 places below Clijsters, refused to be overawed in a tightly-fought second set with Clijsters hanging on to force a tie-break. Clijsters took the tiebreak to win 6-2, 7-6 (5).

But Clijsters, remembered for her epic French Grand Slam final against Jennifer Capriati last year, will have to raise her game on grass to ensure a smooth passage through the Wimbledon draw.

Fellow Belgian Justine Henin also hit a few bumps. Sixth seed Henin battled into the second round with a 6-2, 6-7 (4), 6-1 victory over American Brie Rippner, while No. 16 seed Lisa Raymond was a 6-4, 6-2 winner over Katarina Srebotnik. Monica Seles didn't hit any problems at all as she defeated Eva Bess 6-0, 6-0 in 37 minutes.

Reuters contributed to this report.