Melbourne, Australia, 19 January 2012 | AAP

Lleyton Hewitt has marched into the Australian Open third round as 15th seed Andy Roddick retired hurt in their match at Rod Laver Arena on Thursday night, with the Australian leading two sets to one at the time.

Roddick won the first set, but the match changed complexion when the American stumbled awkwardly during the second, appearing to hurt his leg.

The discomfort was obvious, and it deepened as Hewitt clambered back into the match taking the second set and then the third before Roddick succumbed.

For Hewitt, the 3-6 6-3 6-4 win leaves him alongside Bernard Tomic as the last Australians standing in the singles at Melbourne Park.

Now 30, Hewitt has never won an Australian Open in 15 previous attempts and after a year of injuries and a low world ranking, there have been suggestions this tournament could well be his Melbourne Park swansong.

Yet after years of carrying Australia’s hopes of an Open crown single-handedly and unsuccessfully, Hewitt is now mounting a steady march through a 2012 tournament in which the pressure has been on others.

“In the last four years I’ve had five surgeries, and last year I played just two grand slams and two Davis Cup ties,” Hewitt said.

“I came in here with nothing to lose, I’ll play with my heart on my sleeve and see where it gets me.”

Hewitt now faces 23rd seeded Canadian Milos Raonic in the third round, with a showdown with world No.1 Novak Djokovic in the fourth round looming should he win.