Kenyan David Rudisha sealed a historic Olympic 800m double as Usain Bolt prepared for the next round Tuesday in his quest for sporting immortality.
Rudisha eased to an 800m victory which made him the first man since New Zealand's Peter Snell in 1964 to win the event at consecutive Olympics.
Bolt, 29, in his last Olympics, starts his campaign to add the 200m gold to his 100m title when he takes part in the heats.
Also Tuesday world champion Christian Taylor of the United States attempts to become the first man in 40 years to successfully defend his triple jump title.
And Darya Klishina, cleared at the last-minute following a doping ban, takes part in the long jump as the only competitor in Olympic athletics representing the drug-tainted Russians.
The highlight Monday in track and field was Kenya's Rudisha who was all class in a smooth 800m victory.
"It is great to win such a big competition, my second gold," Rudisha said.
Later came a stunning victory for Brazil's little-known pole vaulter Thiago Braz that sparked an ugly riposte from defeated defending champion Renaud Lavillenie of France.
He likened the atmosphere in the Olympic stadium to the 1936 Munich Games under Adolf Hitler's Nazi regime.
He later apologised, saying he was upset by the unexpected defeat on a night of heavy rain marked by Rudisha's double triumph and an amazing finish in the women's 400m. Favourite Allyson Felix was denied on the line by a headlong plunge from Shaunae Miller of the Bahamas.
Earlier, a wobble on the balance beam ended Simone Biles' bid for a record five gymnastics gold medals, and Rio had its latest safety scare when a giant suspended TV camera plunged to the ground, slightly injuring seven.
Miller remained lying on the track for some time after her unconventional dive left her in significant pain.
"I've never done it before. I have some cuts and bruises, a few burns. It hurts," Miller said.
- Costly wobble -
Her last-ditch plunge meant disappointment for America's Felix, who has Olympic gold medals over 200m, 4x100m and 4x400m but who switched to focus on the longer distance.
Meanwhile Bolt is after an amazing 'triple triple' 100m, 200m and 4x100m relay gold medal cleansweep at three consecutive Games. He said following his 100m triumph two days ago that the feat would make him 'immortal.'
Gymnast Biles was confident of claiming her fourth Rio win and move into position for an unprecedented fifth on the last day of the competition on Tuesday.
But the tiny Texan wobbled badly on the balance beam when landing a forward somersault and had to put both hands down for support.
It was a bewildering upset for Biles, 19, who hadn't lost a final since 2013 but wound up with bronze as the Netherlands' Sanne Wevers topped the podium.
"Everyone would love to have a bronze at an Olympics. I'm just disappointed with my routine. I don't really know what happened," said Biles.
- Hammer record -
At the velodrome, Elia Viviani recovered from a mid-race crash to beat celebrated British sprinter Mark Cavendish in the men's omnium.
"I'm not angry, it's a bike race," said the 27-year-old Italian after the crash, which left South Korea's Park Sang-Hoon in hospital with friction burns and bruises.
Gymnast Eleftherios Petrounias, who is 5ft 5ins (1.64m) and was bullied a child for his lack of height, stood tall for Greece when he won the rings event.
And North Korea's Ri Se-Gwang had tears in his eyes and saluted military-style as he accepted his gold medal in the men's vault.
Off-field hiccups have dogged the Rio Games but there could have been tragic consequences when a suspended TV camera the size of a small motorbike crashed at the Olympic Park precinct.
Seven people suffered minor injuries when two ropes securing the 'spidercam' snapped simultaneously and the camera plummeted 20 metres (65 feet).
Then, as the day closed, a bush fire threatened the mountain bike centre at Deodoro in the west of the city.
Also on Monday, Kenyan-born Ruth Jebet won Bahrain's first ever Olympic gold when she claimed the women's 3000m steeplechase, and Poland's Anita Wlodarczyk broke her own world record en route to the women's hammer title
AFP -- OmRiyadat