Serena Williams showed only glimpses of her best form despite easing into round two with victory over Lourdes Dominguez Lino in a rain-interrupted match.
Williams showed only glimpses of her real class in a mixed display
The American seventh-seed looked ill at ease after a near two-hour rain break, showing real signs of distress when she was broken to trail 5-4 in set one.
But, despite her reluctance to approach the net, her renewed aggression helped her reel off nine straight games.
Spain's Lino could not exploit several Williams errors and went down 7-5 6-0.
In fact, Williams made 20 unforced errors, including six double faults, in a topsy-turvy display.
Lino's best chance of the second set came through two break points in game five, but Williams defended both before seeing out a straight-sets victory.
In the first set I got so upset that I wanted to smash my racket, but as it's partly made of gold I couldn't
Serena Williams on playing with a gold leaf-inlaid racket
Williams, the champion in 2002 and 2003, now faces Australia's Alicia Molik, who beat Anastasia Rodianova of Russia 6-3 6-2.
She later confirmed what her father Richard had said in interviews ahead of Wimbledon - that she has a tight hamstring.
"I'm taking it a day at a time and it's better than it was a couple of days ago," she said. "But I'm glad I've got Tuesday off."
Wiliams added the injury concern would not see her pull out of playing in the doubles with sister Venus.
Belgian top seed Justine Henin enjoyed a more comprehensive victory, beating Argentine qualifier Jorgelina Cravero 6-3 6-0.
Just two games were possible before an extended rain delay, and Henin returned to find Cravero in stubborn mood.
It is really always up and down what I go through in grass-court matches. So it was really good to come through a difficult one
The Argentine's serve was in full flow, forcing Henin to dig deep in the first before hitting top form in the second.
And Henin took the opportunity following her victory to dismiss suggestions that she was considering an early retirment due to injuries.
Her doctor was quoted in a Belgian newspaper suggesting the 25-year-old has just two years left in the game, but she said: "I think that is a bit of a mistake in the paper.
"But, no, it is going to be four, five more years - three certainly depending on injuries but not just two."
On her match against Cravero, she added: "I needed a little bit of time to get used to the surface.
"I couldn't push her much in the beginning but my first-serve percentage was pretty good, and in the end I was beginning to feel much better on the court. I tried to come a little bit more to the net."
On Court 14, Switzerland's Patty Schnyder, the 15th seed, had a marathon match against Camille Pin of France, eventually coming through 6-1 4-6 8-6.
Schnyder had trailed 5-1 in the final set, but fought back for victory, and said: "I played a great first set, but I just could not keep it up.
"Then I struggled with confidence - and it is really always up and down what I go through in grass-court matches. So it was really good to come through a difficult one."
Elsewhere, 19th seed Marion Bartoli of France beat Italian Flavia Pennetta 6-3 6-1, while Israeli 16th seed Shahar Peer beat Tamarine Tanasugarn of Thailand 7-5 6-2.