Faith Kipyegon caused an upset by outpacing Genzebe Dibaba to win the women's 1500 metres and Omar McLeod become Jamaican's first 110m hurdles Olympic champion on Tuesday.
World record Dibaba was expected to add the Olympic crown to the world title she won in Beijing last year, but Kenyan Kipyegon reeled her in towards the end of the back straight and never looked back after hitting the front.
Commonwealth champion Kipyegon took gold in a time of four minutes 8.92 seconds, with Ethiopian Dibaba winning silver and Jennifer Simpson of the United States bronze.
McLeod lived up to his billing as a strong favourite for the final race of the night on day 11, clocking 13.05 to win the 110m hurdles in a field which did not include a solitary runner who had competed in the final at the London games four years ago.
Cuba-born Spaniard Orlando Ortega claimed silver, with France's Dimitri Bascou filling the podium after edging out compatriot Pascal Martinot-Lagarde.
The dominant Christian Taylor retained his triple jump title with a leap of 17.86 metres, with fellow American Will Claye winning silver and China's Bin Dong taking bronze.
Canadian Derek Drouin, a bronze medallist at London 2012, was crowned men's high jump champion after clearing 2.38m, while Croatia's Sandra Perkovic took gold in the women's discuss with a throw of 69.21m.
Usain Bolt coasted into the 200m semi-finals to stay on course for an unprecedented triple triple, while Dafne Schippers laid down a marker in the women's 200m semi-finals by recording a second-fastest time of the year of 21.96.
With the pressure on Dibaba to show her undoubted class in the 1500m final, it was Kipyegon who stole the show by timing her run to perfection.
It was not until two laps from home that the race really burst into life and Kipyegon reacted after Dibaba made her move, getting her tactics spot on to win by a comfortable margin.
No world or Olympic records were shattered, with two-time Olympic gold medallist Taylor unable to put the icing on the cake by passing Jonathan Edwards' mark of 18.29m.
QUOTES OF THE DAY
"Hurdles is all about character. I worked hard, prayed hard and seized the moment. I can't get my mind around this. Is this real? To God be the glory. Now I'm going to eat as much ice cream and cake as I can." - McLeod plans to reward himself after his 110m success.
"I knew it would be a fast race, I really had to kick on the last lap. I was well prepared for the race. I'm proud to win for my country." - Kipyegon reacts to her impressive 1500m victory.
"I had some injuries in the last month and I was not able to train as hard as usual. I had a fierce competitor and I'm happy with my result." Dibaba took her failure to land 1500m gold on the chin.
"I will have enough rest and enough energy to definitely try. But we will see tomorrow how it goes." - Bolt when asked if he will go for the 200m world record after easing into the semi-finals.
Dafne Schippers will aim to make up for the disappointment of failing to land a 100m medal by winning 200m gold on Wednesday, but Elaine Thompson is targeting a sprint double.
Ashton Eaton starts the defence of his decathlon title, while Bolt goes in the 200m semi-finals and there is also the women's 100m hurdles and long jump finals to enjoy as well as the men's 3000m steeplechase final.