Murray will face marathon man Federer

The 25-year-old is now guaranteed at least a silver medal and will have the chance to make it gold in a repeat of last month’s Wimbledon final.

The British No 1 has never beaten Djokovic at a grand slam but the best-of-three-set format and the surface played slightly into the hands of the Scot.

He has managed to take the momentum from his great Wimbledon run into the Olympics and looked particularly impressive in Thursday’s victory over Nicolas Almagro.

Djokovic presented a big step up, of course, but Murray came out supremely aggressive and had two break points in the Serb’s first service game.

He could not take them, but the signs were very good, and when he came under pressure in the seventh game he did not waver, coming through a long game.

The standard from both men was superb as they traded fast and flat groundstrokes, pulling each other all around the court, but it was Murray who had the final say in the first set.

With Djokovic serving to stay in it, Murray brought up his first set point and took it with a curling forehand pass that was agonisingly out of his opponent’s reach.

The Scot roared and Centre Court roared with him, but the job was only half done and Djokovic is a man who never knows when he is beaten.

Murray had to save break points in both his first two service games in the second set as the second seed piled on the pressure, but the break did not come.

Djokovic was certainly not making the most of the openings he did have, and Murray saved another break point in the ninth game, this time with a pinpoint serve.

Player and crowd celebrated together as he held on once more, and amazingly it was the same story two games later, Djokovic by now laughing in exasperation at his failure to break through.

The Serb had been so solid on his serve all set but suddenly he found himself at 0-30 and, when Murray stepped in on a return, he had three match points.

Djokovic has made salvaging such situations a bit of a speciality but not this time, a return from the Scot simply too good and he wept with joy as Centre Court rose to its feet.

Federer is one victory away from his first Olympic singles gold medal after a remarkable 3-6 7-6 (7/5) 19-17 victory over Juan Martin Del Potro.

The match lasted four hours and 26 minutes, surpassing Rafael Nadal’s victory over Novak Djokovic at the Madrid Masters in 2009 as the longest three-set men’s singles match in the Open era.

Federer, who won gold in the men’s doubles with Stanislas Wawrinka in 2008, is now guaranteed at least a silver medal, while Del Potro must recover to battle for bronze against Djokovic tomorrow after leaving Centre Court in tears.

Del Potro had faced Federer five times already this season and lost all of them.