MELBOURNE (AFP) - Roger Federer said on Sunday that he would take on super-fit Briton Andy Murray "any day" over five sets after surviving a marathon match in the Australian Open fourth round.
The Swiss insisted he felt fresh as a daisy after his three-and-a-half-hour work-out against Tomas Berdych and could easily go the distance with Murray despite their six-year age gap.
"I don't know how fit Murray is. I'll take him on any day in a five-setter," Federer said.
"He's younger so he's probably not so experienced. In the end it becomes very mental, and I know that this is where my biggest strength always comes into play. That's why I'm always going to favour myself in a fifth set."
Federer, 27, who has lost his last four matches against Murray, has fought a low-key war of words with the Scot since arriving here.
The 13-time Grand Slam champion pointedly questioned Murray's status as bookies' favourite at the start of the tournament, prompting the Briton to point out "contradictions" in Federer's comments.
The two remain on course to meet in next Sunday's final in a rematch of the US Open title match, where Federer recorded his last win over the 21-year-old Scot.
Fourth seed Murray is seeking his maiden Grand Slam win here and Britain's first since 1936.
