Federer, Sharapova squeeze through

It takes more than talent to make a champion and both Maria Sharapova and Roger Federer needed a sprinkle of that something special yesterday to keep their Wimbledon defences alive.

While there was more base metal than gold in their performances, both managed to do just enough on a day when they would rather have stayed at home.

An off-colour Federer, who had been due to play on Friday before rain wiped out the schedule, failed to stamp his authority on Nicolas Kiefer but had enough in reserve to advance 6-2 6-7 6-1 7-5.

He plays former world number one Juan Carlos Ferrero next after the Spaniard beat Germany's Florian Mayer 3-6 6-2 6-1 6-1.

"That was definitely a test today... definitely," Swiss Federer, who is bidding for a third successive Wimbledon title, said.

"I had the feeling I should've won in three sets but in the end I am happy to have won in four."

Sharapova posted a scrappy 6-2 6-4 win over Slovenia's Katarina Srebotnik and will be happy to have got the first week out of the way at the All England Club.

"The score doesn't say much about the match," second seed Sharapova said. "It was a lot tougher than it seemed.

"Definitely a tough match... every single point, I needed to find a way to win it.

"You know, it's all right. Still got through it without serving great."

Sharapova was joined in the fourth round by 1999 champion and top seed Lindsay Davenport and twice champion Venus Williams. Venus beat Daniela Hantuchova 7-5 6-3.

Serena beaten

Champion in 2000 and 2001, Venus will not face younger sister Serena, champion in 2002 and 2003, in the next round, however.

The American fourth seed Serena was upset 6-3 7-6 by fellow American Jill Craybas in the third round.

Craybas, ranked 85 and aged 30, had never been beyond the third round of a grand slam event but she outplayed the twice former Wimbledon champion on court two.

Davenport strolled through 6-2 6-1 against Russia's Dinara Safina.

"It's probably going to be just a little bit tougher from here on out," she smiled. Davenport faces former world number one Kim Clijsters next. The Belgian beat Italian Roberta Vinci 6-3 6-4.

"Monday's going to be a lot different story," Davenport said. "Kim's not going to let me do that so easily and will get more balls back and will really press me a lot more than I've pressed so far."

Men's second seed Andy Roddick pounded his way past Russian Igor Andreev to reach the last 16. Last year's runner-up, Roddick cranked up his grass-burning serve to devastating effect winning 6-2 6-2 7-6 in one hour 54 minutes.

"I'm still alive, that's the goal," Roddick said. "I feel good going into the second week."

The American will play either Guillermo Coria or Juergen Melzer next.

Mary Pierce advanced. The 30-year-old Frenchwoman, a first-round loser last year, blasted Serbian teenager Ana Ivanovic 6-1 6-4.

Runner-up at the French Open earlier this month, the 12th seed is enjoying her tennis again and the slick lawns are aiding her power game this year. "I'm getting there," she smiled. "Feeling more at ease with each match.

Argentina's David Nalbandian clawed back from two sets down for the first time in his career to spike the challenge of British wildcard Andrew Murray 6-7 1-6 6-0 6-4 6-1 and reach the Wimbledon fourth round.

Former finalist Nalbandian looked to be heading towards the exit after Murray turned the weight of British expectation to his advantage to grab a 4-2 lead in the fourth set.

The Argentine will run into another teenager tomorrow, France's Richard Gasquet.