Venus Williams and Ana Ivanovic thundered into the Australian Open quarter-finals and Roger Federer [Images] overcome his second stern test of the tournament to reach the last eight.

While Wimbledon champion Venus and fourth seed Ivanovic made light work of their opposition, Federer was again made to fight hard to defend his title.

Pushed to five sets on Saturday, he prevailed 6-4, 7-6, 6-3 against 13th seed Tomas Berdych but did not have things his own way.

"He was playing better [than me] in the second set, honestly," Federer said in a courtside interview.

"He got an early lead, then played well in the breaker. In the end, maybe he made a wrong shot selection. It's unfortunate for him, but jeez, it's good for me to win in straight sets."

Next up for the world number one is James Blake who reached his first Grand Slam quarter-final outside the United States with a solid 6-3, 6-4, 6-4 victory over Croatia's Marin Cilic.

Juan Carlos Ferrero takes on fellow Spaniard and almost-namesake David Ferrer later on Monday and the final fourth-round match of the draw pits home hope Lleyton Hewitt [Images] against third seed Novak Djokovic in the night match.

SOME REVENGE

Djokovic's fellow Serb Ivanovic booked her quarter-final with Venus by ousting Caroline Wozniacki 6-1, 7-6.

The world number three has not lost a set during the tournament and is relishing the prospect of playing the Wimbledon champion.

"She's definitely a tough opponent. Last two Grand Slams I lost to her. Exactly the time for some revenge," she smiled.

"It will be important for me to serve well, and, yeah, stay in the court and don't give her too much."

Williams battled into the quarters with a 6-4, 6-4 victory over talented Polish qualifier Marta Domachowska.

Agnieszka Radwanska became the first Polish woman to reach a Grand Slam quarter-final when she came from a set and 3-0 down to beat an ailing Nadia Petrova.

Russian 14th seed Petrova led 6-1, 3-0 but a groin strain hampered her movement in the third set and Radwanska stormed back to win 1-6, 7-5, 6-0 and set up a clash with ninth seed Daniela Hantuchova [Images] of Slovakia.

"I was losing 6-1, 3-0 and I was thinking, 'what am I doing wrong?'," Radwanska told reporters. "It was so quick and she was using the wind very well, and I wasn't.

"Then I started to play, try to do something else. It was very long games and I won the second set. It was so close."

The 18-year-old Radwanska is the youngest of the eight quarter-finalists.

Slovak Hantuchova recovered from a slow start to beat Russian Maria Kirilenko 1-6, 6-4, 6-4.

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