Venus Williams took a lot longer than expected to reach the fourth round of the women's singles at Wimbledon.

The reigning champion dropped the first set against lowly-ranked Canadian Maureen Drake, before belatedly coming to life and winning in three sets - 5-7 6-2 6-1.

Williams lost the first three games against Drake, but pulled back to lead 4-3 before the Canadian came back to take the set 7-5.

Williams emerged a different player in the second set coasted home in the last two sets.

At times she still struggled with her timing, but she raced through the second set before sweeping aside Drake in a torrent of winners on her way to taking the decider 6-1.

"I just had a slow start and I didn't really speed it up the way I would have liked. But I wasn't ready to go home and I wasn't ready to give it up just yet," said Williams.

"If I hadn't found another level I could have been on an aeroplane tomorrow but I've lived to see another day," she added.

Fourth seed Monica Seles also came from a set down to book her place in the fourth round.

The 1992 runner-up got off to a poor start against Japan's Ai Sugiyama but fought back to win 4-6 6-1 6-4 on Court One.

"I started off very sluggishly," admitted Seles. "I had a good wake-up call when I lost that first set.

"It made me play and become more focused.

"But I played well in the second set and the third set. I have come close to losing a set to her in the past and this surface suits her game the most."

Seles will now play Tamarine Tanasugarn in the last 16 after the Thai beat America's Meilen Tu 6-2 3-6 6-0.

Lisa Raymond of the US also made it into the fourth round by beating Spain's Conchita Martinez.

The number 12 seed came from behind against the 1994 women's singles champion to win 2-6 6-3 6-2 and earn a tie against the winner of the Venus Williams-Maureen Drake match.

Also into round four is Bulgaria's Magdalena Maleeva, who saw off 10th seed Silvia Farina Elia, of Italy, 7-6 (7/2) 6-4.

Maleeva, the 19th seed, will face Elena Likhovtseva in the last 16 after she disposed of Britain's Elena Baltacha in straight sets.

Elena Dementieva of Russia, the number 12 seed, was a comfortable winner over 23rd seed Iva Majoli of Croatia 7-5 6-2.

Sixth seed Justine Henin ended the Wimbledon run of 17-year-old Myriam Casanova with a 6-4 6-4 victory on Centre Court.