LONDON, England (AFP) — Novak Djokovic and Andy Murray face an Olympic semi-final showdown after easing through their quarter-finals yesterday, while Roger Federer set up a last four clash with Juan Martin del Potro.

With the winner guaranteed at least a silver medal for the first time in their careers, the clash between world number two Djokovic and Wimbledon runner-up Murray today promises to be classic encounter.

Serbia's Djokovic, a bronze medallist at the 2008 Games in Beijing, looks in good form heading into the last four after defeating French fifth seed Jo-Wilfried Tsonga 6-1, 7-5 on Wimbledon's Centre Court.

Murray has also been in dominant mood this week and the world number four gave a royal command performance as the Duke and Duchess of Cambridge watched him crush Spanish 11th seed Nicolas Almagro 6-4, 6-1 on Court One.

Djokovic has won eight of his 13 meetings with Britain's Murray, including an epic five-setter at the Australian Open earlier this year, but he is well aware he will have to battle a partisan British crowd as well as the dynamic Scot.

"He's going to have big support from the crowd," Djokovic said. "He was close to winning his first Grand Slam just a couple weeks ago so he's motivated as much as I am to win this match.

"Am I going to enjoy to be a bad guy? Well, as I said, he's a home favorite, a hero, somebody that carries tennis in Great Britain.

"The whole nation will be watching and hoping he can get to the finals and win a medal for his country. Obviously I will have to play on top of my game to have a chance to win."

Winning the Games would be the perfect way for Murray to make amends for his Wimbledon final defeat against Federer, but he insists there is no chance he will look past his clash against Djokovic and start dreaming of golden glory.

In the other half of the draw, Wimbledon champion Federer continued his march towards a first singles gold medal with a 6-4, 7-6 (7/5) victory over American 10th seed John Isner on Centre Court.

Federer, a doubles gold medallist in Beijing, found it tough to subdue the 6ft 9in big-server, but eventually cut Isner down to size to reach the last four of the Games for the first time since Sydney in 2000.

"I have my hands full with Juan Martin. He's obviously beaten me in the biggest match we've played against each other, the finals of the US Open. I'm aware of that," Federer said.

Federer has won 12 of his 14 encounters with del Potro, including a fightback from two sets down at this year's French Open, but the Argentine can take heart from his win over the Swiss in that 2009 US Open final.

And Del Potro, a 6-4, 7-6 (7/4) winner over Japanese 15th seed Kei Nishikori, would love to end Argentina's wait for a first medal at this year's Games.

Switzerland's Roger Federer returns the ball to US John Isner during their men's single tennis quarter-final match at the London 2012 Olympic Games in London yesterday. (Photo: AFP)