Andy Murray through to Australian Open quarter-finals

Andy Murray came through his first rocky moments at this year's Australian Open to beat French 'lucky loser' Stephane Robert in four sets and line up a heavyweight quarter-final.

The three-time finalist won 6-1 6-2 6-7 (6-8) 6-2 in two hours and 42 minutes to reach the last eight.

There he will meet the winner of the much-anticipated clash between Roger Federer and Jo-Wilfried Tsonga.

Robert, ranked 119, was outclassed for the first two sets on a blustery and relatively cool afternoon at Melbourne Park, but took the third with a surge of form that saw a fuming Murray smash his racquet in frustration.

The 33-year-old was probably being more sincere than most players when he said before the match that he had nothing to lose, having already been beaten in qualifying.

A late call-up as a replacement to the main draw saw the man who describes his style as "casino tennis" make an unprecedented run to the last 16.

As promised, the Frenchman came out swinging, firing one huge forehand winner down the line in the opening game, but after Murray saved a break point with a big serve, it was one-way traffic for the next 90 minutes.

Twelve winners, several of which came in a run of 11 points in a row, helped him race to the first set in 25 minutes

With plenty of vocal support on his third visit to Hisense Arena - the second show court - the Wimbledon champion powered through nine successive games on his way to a two-set lead.

Robert had given the crowd some entertaining tennis but made barely a dent on Murray's defences.

Three service holds spoke of some more dogged resistance in the third set as he fought off six break points at 3-3, but when Murray crunched a backhand return on the seventh, the win appeared to be as good as his.

It was not quite that straightforward. Suddenly edgy, Murray faced break point in his next service game and was then broken trying to close out the match.

Robert had turned the tables and finally started to get the Briton on the run, moving into a 4-2 lead in the tie-break, before Murray reeled off three attacking volleys and a thumping backhand to earn two match points.

Still the 'lucky loser' refused to yield, and when he battled back to take the set, a forlorn Murray challenged the call before cracking his racquet in anger when it went against him, prompting jeers from the crowd now engaged in a contest they had not expected.

Playing only his second tournament since undergoing back surgery in September, Murray was now being extended into a fourth set for the first time since the US Open - and he did not plan to prolong the match into a fifth.

Murray broke to love for a 3-1 lead and, with Robert now feeling the effects of his seventh match of the tournament, there was no second comeback.

A loud "Come on!" and a fist pump towards coach Ivan Lendl and the rest of Murray's team followed when match point was finally converted, securing a fifth successive Melbourne quarter-final.