Andy Murray was attempting to become the first tennis player to defend an Olympic gold medal. Juan Martin del Potro stood in his way, but Murray overcame the Argentinian in four sets.
Britain's Andy Murray became the first tennis player to successfully defend an Olympic gold medal with a 7-5, 4-6, 6-2, 7-5 victory over Juan Martin del Potro.
The world number two won gold in London four years ago and swept aside his opponent in a dramatic final in Rio, stretching the 29-year-old's current winning streak to a career-high 18.
Del Potro, who defeated Novak Djokovic and Rafael Nadal on his way to the final, added the silver to the bronze he collected in London.
The final will go down as one of the best in the Olympics, lasting over four hours and ending with both men embracing at the net.
"Today was a very up and down match, very stressful. Both of us had a lot of chances and, it was a long and tiring match. I'm just glad I managed to get through it," said Murray.
He ended with 10 aces and 46 crunching winners while del Potro, still ranked 141 in the world after almost two years out through injury, smashed 39 winners but was undone by 57 unforced errors.
Del Potro, a bronze medallist in London four years ago, was inconsolable at the end, weeping as he sat courtside.
The Argentine has fought his way back to the top after undergoing three surgeries.
"What he's had to go through over the last three years or so with his wrists - I can't imagine how mentally difficult that would have been, how frustrating that would have been for him," added Murray.
"To get himself back to playing at this level, fighting for the biggest events and competing against the greatest players in the world is an amazing credit to him. He should be very proud of his efforts."