Former champion Andy Roddick will take centre stage at the US Open on Friday, perhaps for the last time, when he plays rising Australian Bernard Tomic for a place in the third round.

Roddick, the winner in New York in 2003, chose to announce his retirement on Thursday, his 30th birthday, saying it was the right time to go, physically and mentally.

The former World No 1 has always been a crowd favourite but the American is likely to have almost every one of the 23,771 fans inside Arthur Ashe Stadium willing him to victory over world number 43 Tomic.

"I could come out and play great or it could be the worst thing you've ever seen," Roddick said. "I don't know. I've never done this before.

"I'm sure it will be very emotional. I'm sure I'll still be nervous."

Tomic, who reached the quarter-finals at Wimbledon last year, said he was looking forward to testing himself on a big stage again.

"I think if I play well, I can pull off the win (but) it's going to be very difficult," he said. "He's got the crowd here. It's like me playing in Australia. You feel very good. The crowd gets behind you."

Second seed Novak Djokovic continues the defence of his title with a second-round clash against little-known Brazilian Rogerio Dutra Silva, while fourth seed David Ferrer and number nine John Isner are also in action.

In women's play, World No 1 Victoria Azarenka, who has dropped just five games in two matches to date, tries to book a place in the fourth round when she faces China's Jie Zheng, the 28th seed.

Third seed Maria Sharapova takes on American wild card Mallory Burdette while defending champion Sam Stosur plays American Varvara Lepchenko.

British teenager Laura Robson, who ended the singles career of three-times champion Kim Clijsters in round two, faces former French Open champion Li Na of China for a place in the last 16.

Photograph: Michael Heiman/Getty Images