However, in only his seventh match after back surgery, he ran out of steam and Federer eventually clinched a 6-3 6-4 6-7 (6/8) 6-3 victory and a semi-final date with his old rival Rafael Nadal.

Murray found Federer at the top of his game in the first set of their Australian Open quarter-final.

Federer continued his record of not having lost a set this tournament, the only singles player to do so, as he took the opener 6-3 after 31 minutes.

This was their 21st meeting and the first time Murray was the higher ranked.

But his lack of matches after back surgery and Federer’s form in defeating Jo-Wilfried Tsonga in the fourth round meant the Scot was hardly a clear favourite.

Murray drilled a clean winner off his backhand on the first point but soon Federer was pushing forward and making life hard for his opponent.

He brought up two break points in the fourth game and took the first when Murray fired a forehand long.

The fourth seed was playing well but Federer was in rare form, barely missing a first serve and hitting the ball as clean as a whistle off the ground.

Murray held to force Federer to serve out the set, but that proved no problem for the 32-year-old, who took his first set point when the Scot netted a backhand.

Federer has a new bigger-headed racquet this season and a new man in his corner in Stefan Edberg, and both appear to have renewed his confidence.

Federer was open about the doubts that crept into his game last season, partly caused by his own back troubles, but declared them banished following his victory over Tsonga.

Murray appeared confident in his game, too, and was certainly playing at a higher level than he had at any other time in the tournament.

The 26-year-old has consistently shown an ability to step it up against the top players, and this was a real step up after three players outside the top 100.

But two forehand errors in a row cost him in the fifth game as Federer broke to lead 3-2.

Murray was getting close to the Federer serve now but could not engineer a break point, much to his frustration.

It was the same as Federer served at 5-4, Murray placing a backhand agonisingly wide after a long rally at 30-30 and then drilling a forehand long as the Swiss moved to within one set of the semi-finals.

The last time Murray had met Federer was in the semi-finals here last year, when he prevailed in five sets for his first win over the Swiss in a grand slam match.

He would have to go five again to repeat that, but that looked a remote possibility as he hung on grimly at the start of the third set.

Federer forced four break points in Murray’s opening two service games but the fourth seed showed courage to save them all.

The Swiss still looked the better player, though, and he struck once more in the ninth game when Murray netted a forehand.

The British number one was unhappy that umpire Pascal Maria had allowed a Federer lob to stand even though it looked like the ball had bounced twice.

That left Federer serving for the match and for the first time he wobbled, three errors giving Murray his first two break points of the match.

He saved one but on the second a Murray backhand down the line drew the error and he was back to 5-5.

A tie-break would decide it, and it was a real nerve jangler for both men.

Federer looked like he had opened up a decisive lead at 5-2 and he had two match points at 6-4, but Murray played fine attacking points to save both.

The Scot then brought up a first set point and it was Federer who cracked, sending a forehand long as Murray took it 8-6.

Murray appeared to have the momentum and he opted to take a toilet break at the end of the set, giving Federer more time to reflect on his missed opportunities.

But it was Murray who had the mental letdown and found himself facing three break points in the second game of the fourth set.

He steeled himself to save those and then found himself embroiled in a 19-minute game, which he eventually extricated himself from after fighting off three more break points.

But that effort seemed to take its toll, with Murray dropping the speed on his first serve and beginning to look very weary.

He saved another break point to level at 3-3 but the pressure was growing, and when he slipped 0-40 behind at 3-4, Federer finally broke through.

Another twist seemed possible when the Swiss found himself 0-30 serving for the match for a second time, but he reeled off four points in a row, clinching victory with his 10th ace to move through to an 11th straight semi-final in Melbourne.

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