Serena rises above Peer pressure, Vaidisova through

MELBOURNE, Jan 23 (Reuters) Serena Williams needed every ounce of her competitive spirit to prevent Shahar Peer from crashing her Australian Open comeback party today.

Peer, 19, was already in uncharted territory for an Israeli woman by reaching the last eight of a slam and she had one foot in the semi-finals until the seven-times major winner shut the door in her face.

Unseeded Serena, Melbourne Park champion in 2003 and 2005, won 3-6 6-2 8-6 in two hours and 34 minutes after Peer had come within two points of victory.

Peer, showing the toughness one would expect from someone who started mandatory army training in 2005, bossed the match in the early stages but Williams looked the only winner at the death.

''I'm the ultimate competitor,'' she told the Rod Laver Arena crowd. ''I love to compete, I always have even if I'm playing cards or signing autographs the quickest.'' She now faces another formidable opponent in the last four after Nicole Vaidisova triumphed in the battle of the Czech teenagers.

The 10th seed lies in wait for Williams after the mature 17-year-old waltzed past fellow Czech Lucie Safarova 6-1 6-4 to reach her second career grand slam semi.

It took just 71 minutes for her to beat the conqueror of defending champion Amelie Mauresmo, and she now faces her stiffest test against the improving American.

Another success story from coach Nick Bollettieri's production line in Florida, Vaidisova was clearly impressed by one trait she picked up there -- single-mindedness.

''Everywhere I go I have a Czech mind. It's not like when I got to Asia I try to change to my Asia mind, then use my Australia mind. I'm definitely influenced by America, but still keeping my one Czech mind.'' As a bleary-eyed Melbourne Park emerged from the epic Rafael Nadal v Andy Murray clash that finished at 1.51am local time on Tuesday, it will be left to Andy Roddick and Roger Federer to provide the pick-me-up in the men's draw.

It will be a case if better the devil you know for Roddick and former high school friend Mardy Fish when they meet for a place in the semi-finals.

The pair have met five times with Fish only triumphing in the first clash and even then only when the former US Open champion retired in the second set.

But with wins over fourth seed Ivan Ljubicic and 16th-ranked David Ferrer under his belt, Fish -- the walking headline writer's dream -- will be confident of netting another upset.

Only Tommy Robredo's closest confidantes would consider the seventh seeded Spaniard as anything other than roadkill on Federer's inexorable journey to a third Australian Open title.

Robredo won their first meeting at the 2002 Hopman Cup but it has been one-way traffic since with the Swiss maestro crushing the Catalan six times for the loss of just one set.

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