Andy Roddick has claimed a stunning straight-sets victory over world number three Roger Federer in the BNP Paribas Showdown at Madison Square Garden in New York.

In front of 18,000 spectators, the American, who is now ranked 31st in the ATP Rankings, saved two set points in a second-set tie-break before capitalising on his first match point to claim a 7-5, 7-6(7).

Roddick has only beaten the Swiss twice in 23 competitive career meetings.

Following his exhibition triumph, Roddick joked in a post-match interview: "I'm obviously in Roger's head. He had no idea how to play me and I capitalized on that."

Earlier at the event, Maria Sharapova defeated Caroline Wozniacki 6-3, 6-4.