"Lleyton. That's it," the 29-year-old American told his opponent.

He draped his towel over this right shoulder, limped across to umpire Enric Molina, shook his hand, picked up his bag and disappeared down the tunnel at Rod Laver Arena, a 3-6 6-3 6-4 loser.

The pair were expected to bash each other across the Melbourne Park center court until the small hours Friday.

Instead, an awkward off-balance lunge by Roddick early in the second set when he slowly rolled over on his right ankle effectively ended the contest.

The 2003 U.S. Open champion appeared dejected at the end of the game and called for the trainer, took a medical time out, returned and battled for another 16 games, all the while Hewitt was doing his best to run him off the court.

The Rod Laver Arena crowd, so used to cheering on their 'Aussie battler' Hewitt, rose to their feet to show Roddick the respect they felt he deserved.

Hewitt will now meet big-serving Canadian Milos Raonic in the third round.

(Editing by Justin Palmer)