British number one Andy Murray has admitted that he is a big outsider to win this year's Australian Open.

The double Grand Slam champion had surgery on a back injury in September and was then sidelined until December as he recovered from the successful operation.

His return to major competition has gone fairly well so far. He has dropped just one set en route to reaching the quarter-finals at Melbourne Park, but Spain's Feliciano Lopez is the only seed that the Scot has faced to date.

Things will be much harder for Murray from here on in. In order to reach the semis he must beat four-time winner Roger Federer, who defeated 2008 finalist Jo-Wilfried Tsonga 6-3 7-5 6-4 yesterday.

If he is able to overcome Federer, then he will most probably be up against world number one Rafael Nadal in the last four.

Murray told BBC Sport: "I can't honestly say my expectations are as high as if I'd been playing for the last four months.

"It's been a good effort so far to get to the quarter-finals of a Slam this soon after surgery, so I'm happy with that.

"But I'm not far away from winning the event. Anyone that's in the quarters is close."

Murray has won 11 of his 20 previous encounters with Federer, including beating the Swiss 6-4 6-7 6-3 6-7 6-2 in the semi-finals of the Australian Open in 2013.

The majority of the UK bookmakers have Murray as the fourth favourite to win the 2014 title Down Under, behind Novak Djokovic, Nadal and Federer.