Rafael Nadal was confident of being at peak fitness for the Australian Open despite leading a high-profile casualty list at the Sydney International.

The world No.2 handed in-form Australian Chris Guccione a saloon passage into the second round when he retired with hamstring and thigh while trailing 6-5 in the first set.

Nadal's retirement preceded the mid-match withdrawals of seeded Russians Svetlana Kuznetsova and Nadia Petrova from the women's event, leaving tournament organisers red-faced yet again.

Formerly known as the NSW Open, the tournament has been running more than a century but has been tarnished in recent years by a spate of pullouts from players intent on saving themselves for the season's first grand slam at Melbourne Park starting on Monday.

Nadal's withdrawal, while apparently of little concern to the Spaniard, comes on top of Lleyton Hewitt's late scratching with a torn calf muscle and is yet another body blow for organisers.

The top seed required a medical timeout at 3-4, and received some deep-tissue massaging, before eventually calling it quits four games later, just 39 minutes into the contest, on the advice of ATP physiotherapist Clay Sniteman.

"He said if I continue I can get worse," Nadal said, adding he first felt tightness on the flight on Tuesday from Chennai, where he lost to Xavier Malisse in the semi-finals on Saturday.

"The pain started yesterday on the plane and when I go out (to play today) I felt it a little bit more.

"This morning was the same. I go warm up this morning, I don't feel very well.

"But I am trying on the court, but I don't feel 100 per cent." Nadal, who missed last year's Open with a chronic foot injury, insisted he was in no doubt for the 2007 event.

"I'm going to play for sure," he said.

"There's nothing broken. It's tight, too much tight.

"I hope in two more days I will be 100 per cent because I want to play the Australian Open for sure.

"It's very important for me and last year I couldn't play and this year I want to play there.

"I enjoy it a lot. It's one of my favourite places, maybe one of my favourite tournaments of the year.

"I play very good every time there ... it's very special and (Rod Laver Arena) is my favourite centre court."

Nadal planned to fly to Melbourne on Wednesday and will continue receiving treatment, which will include stretching and anti-inflammatory shots, before hopefully resuming practice on Thursday.

Guccione's walkover advanced the 21-year-old to a second-round clash on Wednesday with Austrian lefthander Juergen Melzer.

While Nadal and also Thailand's Paradorn Srichaphan were unable to complete their first-round matches today, defending Sydney champion James Blake comfortably advanced with a 6-3 6-4 win over fellow American Kevin Kim.

Sixth-seeded Richard Gasquet downed French countryman Julien Benneteau 6-1 6-4, while veteran Spaniard Carlos Moya survived a match point to deny gallant Australian wildcard Luke Bourgeois 7-6 (7-4) 4-6 7-6 (8-6).

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