Britain's Andy Murray became the first tennis player to win two Olympic singles titles by beating Argentina's Juan Martin del Potro in Rio.
An emotional Murray, 29, secured a thrilling 7-5 4-6 6-2 7-5 victory to make it GB's most successful day at an overseas Games with five gold medals.
The see-saw match featured 14 breaks of serve in front of a raucous crowd.
Murray's win comes five weeks after he claimed his second Wimbledon title and four years after London 2012 success.
Both men looked exhausted in the fourth set of a gruelling four-hour contest, with Murray breaking down in tears after finishing off his gritty opponent.
The crowd on Centre Court were boisterous throughout, with plenty of Argentine support for 27-year-old Del Potro, although emotions did spill over near the climax when two fans were ejected.
Murray said the final was one of the toughest he had played in and cast doubt on the chances of winning a third gold in Tokyo in 2020.
"Four years is a long time and so many things can change," he said. "Who knows about Tokyo? At 33, I'm not sure I'll be at the same level."
Del Potro's silver medal signifies his continued return to form, with his past three seasons disrupted by a wrist injury.