Melbourne - Juan Del Potro made a late start to his 2013 tennis campaign, beating Paul-Henri Mathieu of France 6-4, 3-6, 7-6 (7-3) to advance on Wednesday at the Kooyong Classic tune-up event.
The Argentine who played off-season exhibitions at home with both Roger Federer and the retired Andy Roddick, may be top-seeded at the eight-man special event which is considered elite preparation for the Australian Open starting next week.
But the South American ranked seventh is hesitant to rate himself among the tennis elite despite holding a US Open title from 2009.
"Rafa, Roger, Djokovic, Murray - Rafa is coming back soon, I think - are the favourites," he said of the upcoming year in which Nadal will miss playing the first major after nearly seven months of knee injury problems.
"He's still working on his knees and will be back very, very soon. That's good for tennis and for us. It's going to be great to see him playing again.
"This group is the best group of the world and we try to get closer to them day by day, but it is not easy."
Del Potro won as Mathieu, a late substitute for injured Argentine Juan Monaco (hand injury) double-faulted on match point.
Del Potro moves onto the promotion round, where he plays 2007 Melbourne finalist Marcos Baghdatis, who won 6-1, 1-0 when Serb Janko Tipsarevic had to quit with an existing wrist injury. That marked the third medical withdrawal of the tournament after Japan's Kei Nishikori pulled out with a knee problem and was replaced by Croatian Ivan Dodig.
Tipsarevic won last week's Chennai tournament playing with painkillers, a luxury he did not allow himself at Kooyong in order to test the problem.
Australian Lleyton Hewitt engineered a tight 6-3, 1-6, 7-6 (7-4) victory over Milos Raonic, despite 20 aces from the Canadian ranked 13th.
Hewitt, 31, won the tune-up title in 2011 and will be starting in a record 17th straight Aussie Open on Monday.
Hewitt will be playing in a record 17th-straight Australian Open when the first major of the season starts on Monday. And the former number one, Wimbledon and US Open champion could not be more pleased to be competing pain-free after several years of foot and toe problems.
"I feel mentally fresh and just excited to be playing without pain," said Hewitt, who has undergone two foot surgeries in recent seasons. "The last few years have been frustrating, trying to play with injuries.
"I'm amazed at how many Opens I've played, but I don't focus on the record - it only makes me think how old I am. But when I retire I'll be pretty proud of it."