By Joshua Schneyer
RIO DE JANEIRO (Reuters) - 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 successfully defend the title.
Murray gripped his head and tears welled up after he clinched match point when he broke del Potro's serve for the ninth time, then shared a long hug with the Argentine at the net.
It was the world number two's 18th successive victory after he also clinched his second Wimbledon title in July. He did not play again after the grass court grand slam until the Rio tournament.
The Briton had been a hot favorite to retain his title, despite del Potro's form on the hardcourts in Rio.
Del Potro, whose ranking has slipped to 141 after a series of wrist injuries over the past six years have kept him out of the game for prolonged periods, beat top seed Novak Djokovic and Spain's Rafa 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 dropshots.
Though the players traded service breaks throughout the match, Murray proved more consistent in the end.
The Scot also faced a rowdy crowd that included hundreds of Argentine fans waving national flags and chanting like at a soccer game to cheer on their compatriot in the first Games held in South America.
Such was the noise, the chair umpire had to resort to telling the crowd in Spanish to be quiet.
It was also del Potro's second Olympic medal after he won bronze in London.
Japan's Kei Nishikori earlier beat Nadal 6-2 6-7(1) 6-3 to clinch bronze.
Nadal won the men's doubles gold with Marc Lopez on Saturday.
(Editing by Ed Osmond/Greg Stutchbury)