Williams sisters loom over event

Serena and Venus Williams aim to maintain a decade of dominance at Wimbledon from Monday with their fearsome reputations so established that even world No 1 Caroline Wozniacki is desperate to avoid contact.

At least one Williams sister has appeared in 10 of the last 11 women's singles finals, when Venus downed Lindsay Davenport in straight sets to claim her maiden Grand Slam triumph.

Since then the sisters have turned Wimbledon into a personal fiefdom, winning the title on nine occasions - Serena with four, Venus with five.

"No one wants to play them. They have the experience and play really well, especially on grass," said Wozniacki.

"It's good that they got a higher seed than their rankings because no one wants to play them in the early rounds."

But the $2.9 million question - the record purse on offer to this year's champion - is the extent to which lengthy injury lay-offs have diminished the power of the all-conquering US duo.

Until her appearance at last week's Eastbourne WTA event, Serena had not played since last year's Wimbledon final, where she swatted aside Russia's Vera Zvonareva in straight sets.

Since that imperious victory, the 29-year-old 13-time Grand Slam title winner has struggled with a life-threatening health problem after also suffering serious injury when her foot was sliced open by broken glass.

Serena, who has been seeded seven, insists she arrives at Wimbledon merely grateful that she is in the draw, and claims to have put aside thoughts of defending her crown.

"I'm just taking everything one day at a time, and I'm not putting too much expectation on myself or on my game," said Serena, who starts her campaign against France's Aravane Rezai.

The effects of her extended lay-off were plain to see at Eastbourne, where she struggled past Tsvetana Pironkova 1-6, 6-3, 6-4 before exiting against Zvonareva in the second round, 6-3, 6-7 (5/7), 5-7.

Elder sister Venus is in a similar position, also returning from injury at Eastbourne this week after a prolonged absence.

The 31-year-old elder Williams sister has hardly played since the Australian Open in January, when she retired after one game of her third-round match against Andrea Petkovic after suffering an abdominal injury.

Venus avenged that loss to Petkovic in the first round at Eastbourne before dismantling Ana Ivanovic 6-3, 6-2 to reach the last eight. She then exited at the hands of Slovakia's Daniela Hantuchova.

"I feel good about my preparation," said 23rd-seed Venus, whose first-round opponent will be Akgul Amanmuradova of Uzbekistan.

"I thought I played pretty good. More than anything I was able to get a lot of great competition."

While the Williams sisters are far from their respective peaks, it remains to be seen which of the pretenders to their Wimbledon throne are best placed to exploit the potential vulnerability of the Americans.

Wozniacki, who faces Spain's Arantxa Parra Santonja in the first round, has the top seeding and the world No 1 ranking.

But with only one Grand Slam final appearance in her career, few are expecting the 20-year-old to break her duck on grass, her least favourite surface.

"My main goal this year is to be a Grand Slam champion," Wozniacki said. "I want to win one. It would be disastrous if I could not make it happen. I just want to enjoy every time I play on the court."

Much interest will centre around the campaign of China's Li Na, the newly crowned French Open champion who has reached the final of both majors so far this season.

Li's victory at Roland Garros was watched by an estimated 100 million people in her homeland, and she is determined to prove that her performance in Paris was no flash in the pan.

"If I don't do well at Wimbledon, maybe people forget me already. These are tough times, you know," Li said.

With world No 2 Kim Clijsters withdrawing through injury, a potential dark horse is fifth-seed Maria Sharapova, the only woman to record a victory over one of the Williams sisters in a Wimbledon final.