Serena Williams conceded she was struggling with a hamstring injury after surviving a trip to the 'Graveyard of Champions' at Wimbledon on Monday.

Williams' pre-tournament declarations of being in prime physical shape appear to have been nothing more than a smokescreen after her outspoken father Richard admitted his daughter was not fully fit.

Seventh seed Williams was certainly not at her best against Spain's Lourdes Dominguez Lino, a player ranked 57th in the world, but she still summoned up enough craft to advance 7-5 6-0 on Court Two - an arena renowned for staging the demise of former winners at SW19.

Afterwards, when quizzed about the hamstring problem, she said: "It's doing okay, I am just taking it a day at a time. It's better than it was a couple of days ago. It's improving slowly but surely.

"I am glad I have tomorrow off, that will help. I will continue to have it looked after."

Williams' second-set performance was vastly superior to that in the first when she struggled to find her range.

A 90-minute rain delay at 3-3 certainly didn't help but two-time Wimbledon champion Williams was not offering any excuses.

She added: "I think I raised my game on some points in the second set but overall out of 10 I would only give myself a two, if I was lucky.

"I hit a lot of double faults which I don't normally do so that was strange."

Williams can count herself a touch fortunate to have wrapped up victory in straight sets.

The delay due to the inclement weather seemed to throw her completely off course.

When the players returned, she struggled to regain any rhythm. A host of poor ground strokes gifted Dominguez Lino two break-points in the ninth game, the second of which she took when the American pushed another woeful forehand wide.

But Williams broke back immediately and coasted through her next service game to reassert her authority at 6-5 and place the pressure firmly back on the Spaniard.

Dominguez Lino buckled as Williams finally began to show the kind of power game which has carried her to seven Grand Slam titles.

An early break in the second set confirmed Williams' superiority and she never looked back.

Two further breaks followed as Williams cruised through to a second round clash against Australia's Alicia Molik.