TENNIS: Officials wickedly tempted fate again. The novelty of outside courts evidently offers the fans a spectacle, but this is surely addling the minds of top seeds.

Following the demise of Pete Sampras and Kim Clijsters on Court Two earlier in the week, Serena Williams came spookily close to understanding just why it is regarded as the graveyard, her intended victim Els Callens gamely refusing to be consumed in one sitting.

Her service broken by the 119th-ranked Belgian in the first set, Williams had to break back then reach for a tie-break as she struggled for 50 minutes to keep her feet and at times her composure.

The number two seed ended up on the flat of her back five times and was forced into playing a strategy where she gingerly avoided sharp changes of direction. Even for a number two seed facing a player who has never won a tour title in all of her 31 years, that, as they say in rugby, is a big ask.

But Callens, throwing junky shots of spin and slice from the back and coming in, clearly upset the American, and when Williams dropped her serve in the second set and was forced to come back from 4-2 down, she had again entered a zone she had not yet previously experienced this year in the championships. Neither of her previous opponents managed to take more than three games in any set.

Ultimately her predatory instincts and immense strength kept her alive, Callens efforts fading only in the second set tie-break as Williams, whose unforced errors rose to 22, finally imposed herself on the game and scraped through after one hour and 39 minutes 7-6, 7-6.

More relieved and frustrated than excited, the younger Williams sister was not a happy player afterwards.

"It was definitely very close," said Williams. "I think Ms Callens played out of her mind today. Eveytime I play her in doubles she gives me a hard time. I wasn't surprised at all. But I never believe I'll lose. Never."

Williams' father and coach, Richard, didn't travel to England this year because of illness, an issue the players say is unimportant.

"I'll talk to my dad about the match. He wasn't at the French Open. He's a bit busy right now but I'm sure he'll have watched the match on TV and I'll talk to him.

"I wasn't converting my break points. I was nervous to move because every time I moved I'd slip or fall, especially in the first set," she said.

Finishing off first week fodder also demanded a little labour from seventh seed Jelena Dokic. The 19-year-old, who as a qualifier in 1999 and ranked at 129, provided one of the biggest upsets in the Open era when she defeated number one Martina Hingis in the first round, struggled to supress 28th-ranked Nathalie Dechy.

Dokic survived several set points despite initially taking a 5-2 lead, then sought a tie-break for the first set. The second she won with ease 6-2 but the impression that hung in Centre Court was one of a player unable to close out opponents when under pressure.

"I was a lot happier than the other day," said Dokic before being asked about her link with Formula One driver Enrique Bernoldi.

"If I wasn't a tennis player, you wouldn't be asking me that right now. So why don't you think of a question that is your business and you can ask me that."

In danger of filling the Kournikova vacuum, Dokic is already being billed as the main lead in the next round "glamour" match with starlet and 12th seed Daniela Hantuchova, who advanced against Maja Matevzic 6-4, 6-4.

Jennifer Capriati continued to quietly beat her way through the week with a little less trauma. The third seed admitted to dozing off during her match against Daja Bedanova but as one of the natural fighters in the women's game, her passage was not difficult, wininng 6-4, 6-2.

"On the tennis court I look on it as a battle," said Capriati. "It's something that has always been part of me. Especially the last few years of my life, I've really had to fight on and off the court."

Amelie Mauresmo ended the hopes of 20-year-old Russian Anastasia Myskina in two sets. The more experienced French player advanced to the fourth round for the first time in three visits and now meets Laura Granville in the next round.

Granville, making her Wimbledon debut, defeated French Open quarter-finalist Mary Pierce in three sets for the biggest win of her career. The fourth round prize money of £31,250 is almost as much as the 21-year-old's entire prizemoney to date.