Nadal on form as Murray crumples in fourth round

But the Spaniard is keeping his expectations in check. "I'm playing well, but you never know if it's gonna be enough," he said after an 18th Melbourne victory. "I hope to keep playing like this, we will see.

 "All the matches are very, very difficult. The next (v Gilles Simon) will be very tough.  I have to be ready for everything."

   Andy Murray became the most notable victim so far as he went down to Spain's Fernando Verdasco 2-6, 6-1, 1-6, 6-3, 6-4.

 Murray, who was on his sick bed at times last week, came to Melbourne with a title in Doha to start the season and wins over Roger Federer and Nadal in 2009.

 The 14th seed Verdasco refused to bow, firing 52 winners to 51 for the Scot.

 "I had my chances, he served incredible in the fourth and fifth sets," said the fourth seed. "He deserves the credit for the win.

 "I'm disappointed that I lost.  But I'll try and learn from it. I want to win every match that I play, but I'm not going to get down about it.

 "I worked very hard in the off season.  It's been a good start to the year."

   Chilean Gonzalez broke Nadal early in the third set but was unable to hold onto the precarious margin as the top seed leveled in the sixth game and powered through in fine style, still without dropping a set since the start.

 Upcoming opponent Simon was one of three players on the day who benefited from retirements from injured or ailing opponents.

 The sixth seed reached his first Grand Slam quarter, a 6-4, 2-6, 6-1 victory blighted by the retirement of opponent Gael Monfils with a right wrist injury.

 "Of course I didn't want to win like this," said the Frenchman. "I'm sorry, but that is tennis. But I have a quarter-final to play in two days, and I just have to focus on this."

   France could duplicate a 2006 Melbourne Park showing by placing two men into the last eight if last year's finalist Jo-Wilfried Tsonga beats James Blake.

 Three-time women's champion Serena Williams and eighth seed Svetlana Kuznetsova also escaped the fourth round the easy way on the Australian Day holiday

   Kuznetsova moved through as China's Zheng Jie quit just five games into their match trailing 4-1, victim of a hand problem .

 Williams was on court for just under 90 minutes when 13th seed Victoria Azarenka succumbed to the effects of a virus, handing over a 3-6, 4-2 win.

 The 27-year-old Williams stayed in the race for the WTA number one ranking held by defeated Jelena Jankovic, chasing along with Elena Dementieva, a 6-2, 6-2 winner over Dominika Cibulkova, and Russian Dinara Safina.

 Unfancied Carla Suarez Navarro continued to excel as she reached the quarters over Spanish compatriot Anabel Medina Garrigues 6-3, 6-2.

 Williams will next play Kuznetsova, who took her own good luck in stride when her Chinese opponent pulled out before the fifth game.

 "I felt sorry for her because she was in great shape," said the Russian. "She was playing good. This pain I hope is not very dangerous."

   Zie was unable to get a proper scan due to the holiday but said that her wrist just packed up on her without much warning. - DPA