Usain Bolt cruised into the final of the men's 200 metres at Rio 2016 as Justin Gatlin failed to qualify, while Elaine Thompson recorded the first women's sprint double since 1988 with victory over the same distance.
Bolt kept his bid for an unprecedented triple-triple on track by winning the second semi in 19.78 seconds, just ahead of Andre De Grasse (19.80secs), who valiantly tried to run him down on the line.
The pair were able to share a joke as they crossed the finish line, but Gatlin's semi-final proved a sobering experience for the American, who missed out on the final after easing up too early, although he blamed his performance on an ankle injury.
Meanwhile, Thompson made history by holding off 200m world champion Dafne Schippers of Netherlands to add another gold to the one she claimed in the 100m.
The women's 100m hurdles saw a clean sweep for the United States, Brianna Rollins winning in a time of 12.48secs ahead of compatriots Nia Ali and Kristi Castlin.
There was more joy for USA in a thrilling long jump competition in which Tianna Bartoletta took the gold with a personal best of 7.17 metres to edge out team-mate Brittney Reese (7.15m). Ivana Spanovic of Serbia had to settle for bronze despite a national record jump of 7.08m.
Kenya's Conseslus Kipruto triumphed in the 3000m steeplechase ahead of American Evan Jager, but two-time Olympic champion Ezekiel Kemboi was stripped of his bronze for stepping outside the track limits following a successful protest by the French team, with Mahiedine Mekhissi taking the third step on the podium instead.
Defending champion and overwhelming favourite Ashton Eaton leads by 121 points in the decathlon.
Although Bolt delighted his adoring public with another dominant performance, it was his Jamaican compatriot Thompson who stole the show as she upstaged overwhelming favourite and world champion Schippers to clinch her second gold of the Games.
Thompson went into the home straight with the advantage despite a fast start from Schippers and was able to maintain a gap to triumph by a tenth of a second, crossing the line in 21.78secs to become the seventh woman to do the sprint double.
No world records were broken on day 12 but Kipruto set a new Olympic record in his 3000m success, prevailing in a time of eight minutes and 3.28secs.
QUOTES OF THE DAY
"It's a showman's sport. I think the rivalry that I have with Usain, it's turned it into a professional wrestling feel. Everyone's cheering for Usain, but they have someone they have to boo against," - Gatlin sees elements of the WWE in his rivalry with Bolt.
"I can't wait until I can eat a pizza," - Bartoletta is ready to treat herself after the dominos fell into place in the long jump.
"He was supposed to slow down. I said 'What are you doing, it's a semi-final?' But I think he wanted to push me. I was a bit lazy but I got round," - Bolt reveals the details of his joke with De Grasse.
Bolt will seek to take the next step towards the triple-triple in the 200m final, while the final day of the decathlon sees Eaton aim to seal a second straight Olympic title. Medals will also be up for grabs in the men's and women's 400m hurdles, the men's shot put and women's javelin.