Usain Bolt enshrined himself in the Olympic pantheon when he won the 200 metres to complete an extraordinary double-double on Thursday, but for once he shared the limelight as Kenya's David Rudisha stormed to a stunning world record in the 800m.
Bolt, who imperiously led home a Jamaican medal sweep in 19.32 seconds, is undoubtedly the world's fastest man and almost certainly the greatest-ever sprinter but the title of the world's best athlete belongs to American Ashton Eaton who won the Olympic decathlon title.
There were also golds for American Christian Taylor, who produced the year's biggest triple jump of 17.81m to beat compatriot Will Claye, and for Czech Barbora Spotakova who successfully defended the women's javelin title.
The field events were a mere backdrop, however, for Bolt's assault on the history books as the first man to win two 200m golds and the only one to retain both sprint titles following his world record double in Beijing
He sent the 80 000 crowd into a frenzy for the second time in five days when he followed up his 9.63 100m success, the second-fastest time ever, with the equal fourth-quickest 200m.
Yohan Blake, runner-up behind his training partner in the 100m, finished second in 19.44 with Warren Weir completing a surprise Jamaican sweep in a personal best 19.90.
Bolt ran a stupendous bend to put the race in his pocket and with his eye on the clock he eased down slightly over the final few metres.
"This is what I wanted and I got it. I'm very proud of myself," he told reporters.
"After a rough season I came out here and did it. I thought the world record was possible. I guess I was fast but not fit enough. I could feel my back strain a little bit."
Pushed relentlessly in dozens of interviews Bolt declared his "legend" mission to be accomplished, tossing in the claim that "I am the greatest athlete to live."
Few in the stadium would have argued, though they had already been treated to another supreme performance by Rudisha, whose first athletics world record of the Games was emphatic both in execution and result.
Olympic 800m finals are often tactical affairs but Rudisha, far and away the fastest man in the field, decided to take no chances and hit the front from the start.
After a blistering 49.28 first lap there was no consolidation, no steadying down, just a relentless application of power and pace as the field were strung out in a stretched single file behind him despite most of the athletes running the race of their lives.
Rudisha, tall and beautifully balanced, took a tenth of a second off his own two-year-old world record with his winning time of one minute 40.91 seconds.
Eighteen-year-old Nijel Amos collected Botswana's first-ever Olympic medal and a world junior record when he finished second in a time of 1.41.73, which might sound familiar to London 2012 Games head Sebastian Coe as it was the world record he set in 1981 that stood for 16 years.
"Instead of just doing enough to win the race he wanted to do something extraordinary and go for the world record as well," said Coe, who won two Olympic 1 500metre titles but only two silvers in his preferred shorter event.
"Rudisha's run will go down in history as one of the greatest Olympic victories."
"Rudisha's run will go down in history as one of the greatest Olympic victories. I feel privileged to have witnessed it."
Kenya's Tim Kitum took bronze as seven of the eight finalists ran personal bests, including last-placed Briton Andrew Osagie, whose time of 1:43.77 would have been good enough to win the last three finals.
Eaton came into the Games as a similarly hot favourite having set a world record in the US trials and the 24-year-old barely put a foot wrong from the opening 100 metres on Wednesday morning through to the concluding 1 500metres on Thursday evening.
He held a 220-point lead going into the second's five events but compatriot Trey Hardee cut that to 99 after the 110 hurdles and discus.
Eaton, however, cleared 5.20 in a marathon pole vault in boiling conditions and threw a personal best of 61.96 in the javelin as he ended on 8 869 points, 198 ahead of Hardee. Cuba's Leonel Suarez collected bronze for the second Games in a row.
There was drama in the morning qualifying for Friday's 4x400m relay as two medal contenders, Jamaica and Kenya, failed to advance after an injury and a collision while South Africa were handed a bonus place in the final on appeal after failing to finish.
Jamaica will hope to make amends in the 4x100m relay, which they won with a world record four years ago, and they go in Friday's heats when Bolt is likely to be rested for Saturday's final - the last track event of the 2012 Games.