- Andy Murray - Australian Open - Gilles Simon - tennis
AFP - Briton Andy Murray motored into the Australian Open second round on Tuesday while Australia's Lleyton Hewitt's comeback from injury stalled as he became a high-profile casualty.
Last year's runner-up Jo-Wilfried Tsonga kept up the seeds' perfect record here with world number one Rafael Nadal due to open his campaign later.
Murray was cruising at 6-2, 3-1 against Andrei Pavel before the 34-year-old retired with a long-standing back injury, and then quit tennis for good.
"Obviously you don't want to finish a match like that. Andrei's been having problems with his back for a year," said the world number four.
"It's unfortunate he had to stop but I felt like I was hitting the ball well."
While Murray is seeking his first Grand Slam title, Hewitt already has two in the bag but a third looks increasingly remote after his loss to 13th seed Fernando Gonzalez.
Hewitt, 27, showed flashes of his battling best as he forced a fifth set with the Chilean before running out of gas as Gonzalez took it 5-7, 6-2, 6-2, 3-6, 6-3.
But the former number one, who is returning from hip surgery, refused to contemplate retirement and vowed to fight his way back into the top 10.
"He's a tough player to play against for anyone, even the best guys like Roger (Federer), Rafa (Nadal), purely because he wants to play on his terms," Hewitt said.
"He's always gonna be the guy trying to dictate play. If he's able to dictate play, then he's extremely tough to beat."
Hewitt has been eclipsed here by fellow Australian Bernard Tomic, 16, who sparked a media storm when he became the tournament's youngest male winner ever on Monday.
But he warned the youngster had yet to prove himself as a top player.
"It was a great win by Bernard on Monday, but he's still got a long way to go before he's in the top 100 and playing in the other Slams, the other Masters Series week in and week out," Hewitt said.
"I could be retired by the time he gets to top 100. Who knows how long that will take."
French livewire Tsonga electrified Melbourne Park with his run to last year's final and he was again impressive winning 6-4, 6-4, 6-0 against Juan Monaco, shrugging off a recent back injury.
"I try to play my best every time -- I just try to be as good as I can be," he said.
Seventh seed Gilles Simon thrashed Spain's Pablo Andujar while Richard Gasquet and Gael Monfils completed a good day for the French.
But Asia's slim hopes took a knock when Japanese prodigy Kei Nishikori fell at the first hurdle against Austria's Jurgen Melzer.
"No, I didn't have any pressure because, of course, he's good and he's seeded. I just didn't play well today," he said.
Nadal opens his campaign against Christophe Rochus of Belgium in Tuesday's late match. Three-time winner Roger Federer won his first match late on Monday, joining defending champion Novak Djokovic in the second round.