RIO DE JANEIRO • Britain's Andy Murray beat Argentina's Juan Martin del Potro 7-5, 4-6, 6-2, 7-5 in a compelling and gruelling Olympic tennis final on Sunday to become the first player to win back-to-back singles gold medals at the Games.

Murray gripped his head and tears welled up after he clinched match point when he broke del Potro's serve for the ninth time, before sharing a long hug with the Argentinian at the net.

It was the world No. 2's 18th successive victory after winning his second Wimbledon title in July.

The Briton had been a hot favourite to retain his Olympic title, despite del Potro's form on the hardcourts in Rio, where he vanquished top seed Novak Djokovic and doubles gold medallist Rafael Nadal to reach the final.

On Sunday, Murray was able to wear down del Potro by hammering ground strokes to his weaker backhand, and frequently drawing him into the net with deftly placed drop shots.

Though the players traded service breaks throughout the match, Murray proved more consistent.

"Tonight was one of the hardest matches I have played," he said in the bowels of the Olympic Tennis Centre, a British flag draped round his shoulders. "I know the fact it (defending the title) has not been done before means it is very hard to do, and I am very, very proud to be the first one to have done it.

"Four years is a long time, a lot can happen. I had back surgery between London and now... I've gone through some tough times on court."

In the bronze-medal match, Kei Nishikori won Japan's first Olympic tennis medal in almost a century when he defeated Nadal, despite the weary Spaniard mounting a stirring mid-match fightback.

Nishikori triumphed 6-2, 6-7 (1-7), 6-3 to become the first Japanese to win an Olympic medal since Antwerp in 1920 when his nation won silver in both the men's singles and men's doubles events.

REUTERS, AGENCE FRANCE-PRESSE