Golden goodbye as Phelps signs off with 23

Rio de Janeiro : Michael Phelps brought down the curtain on his record-breaking career with his 23rd Olympic gold medal as Mo Farah stole the show at the athletics with a gritty 10,000m win on Saturday.

Ryan Murphy broke a seven-year-old world record in the backstroke leg of the 4x100m medley relay, but Phelps still needed to come from behind on the butterfly before Nathan Adrian touched in a new Olympic mark of 3min 27.95sec.

It was a fittingly triumphant swansong for Phelps, 31, the most decorated Olympian in history who added five golds and a silver in Rio to finish with 28 medals overall.

Earlier the United States also won the women's 4x100m medley relay -- the country's 1,000th gold medal in Olympic competition according to the US Olympic Committee.

Usain Bolt launched his bid for the 'treble-treble' by cantering through the 100m preliminaries but all eyes were on Farah as he survived a nasty fall to retain his 10,000m crown.

Farah picked himself up after being clipped by training partner Galen Rupp and he produced a trademark surge on the last bend to win it in 27min 05.17sec.

"When I went down, I thought, 'Oh my God, that is it.' I just got up and wanted to stick with the guys and stay strong," Farah said. "It's never easy but everyone knows what I can do."

Elaine Thompson ended the reign of Shelly-Ann Fraser-Pryce with a women's 100m victory of 10.71sec which torpedoed her fellow Jamaican's hopes of an Olympic hat-trick in the event.

Tori Bowie of the United States took silver with 10.83sec while Fraser-Pryce claimed bronze in 10.86.