While millions would already consider Bolt a legend for winning triple gold in Beijing and defending his 100m title at London 2012 on Sunday, the Jamaican insisted he also had to retain his 200m title to achieve such status.
And the 25-year-old did precisely that with another imperious performance, leading a Jamaican clean sweep ahead of 100m silver medallist Yohan Blake and Warren Weir, both of whom are just 22.
'I'm now a living legend, I'm also the greatest athlete to live,' said Bolt, who said he gave up on breaking his own world record of 19.19 after feeling a twinge in his back coming off the top bend, settling for winning in 19.32.
'Now I am going to sit back, relax and think about what's next. I don't know what I really want to do after this, whether to run the 100 or 200 or try something else. I need to find a (new) goal that's going to motivate me to great things.
'But I am not ready to retire. I love this sport. The rest of the season I am just going to have fun because I did what I came here to do.'
Rudisha made the most of ideal conditions, storming through the first lap in 49.28 and powering to the gold medal in 1:40.91.
There was success for the USA as Christian Taylor added the Olympic title to his world Triple Jump crown and Ashton Eaton claimed Decathlon gold.
The final gold medal of the evening went to Czech Barbora Spotakova, who successfully defended her Javelin Throw title with a best effort of 69.55m.