Usain Bolt began his bid to add a second Olympic 200 metres crown to his two 100m titles with a hugely comfortable heat victory today.
The Jamaican, who clocked an Olympic record 9.63 seconds to retain his 100m crown on Sunday, cruised to victory in 20.39secs.
Bolt has said he needs to win 200m gold again before he achieves his aim of becoming a "legend".
"It was an easy run, I'm enjoying it, it's my favourite event," said Bolt.
"It's getting pretty chilly. They say the weather should be good on Thursday [for the final] so we'll see."
Asked what he did to celebrate his 100m success, he said: "Nothing. I just chilled, met some friends and sat and talked."
Bolt's countryman and training partner Yohan Blake also breezed through, slowing down well before the line to clock 20.38s.
Blake had to settle for silver in the 100m, but is out to deny Bolt a second gold, having beaten him over 200m at the Jamaican trials
France's Christophe Lemaitre went quicker than both Jamaicans in winning his heat in 20.34 and Bolt nodded in approval as he watched his rival's run on a TV screen.
Blake, dubbed 'The Beast' because of his prodigious work ethic, said: "I did what my coach said and qualified. I'm feeling good, that's why they call me the beast. The track is fast.
"I appreciate anything is possible.
"The 100m taught me a lot and it's given me confidence. I love this event."
Asked whether he could beat Bolt, he said: "I'm not really focusing on beating him. I'm concentrating on running my race."
Ecuador's Alex Quinonez was in fact the fastest qualifier in a national record of 20.28.
World number one Aries Merritt qualified impressively in the 110m hurdles in 13.07 as China's Liu Xiang crashed out injured at the first hurdle.
Merritt said: "The track is blisteringly fast. The time (in the final) is going to be extremely fast."
World triple jump champion Christian Taylor took just one jump to book his place in the final, leaping 17.21m with his first effort.
Olympic champion and world record holder Barbora Spotakova topped qualifying in the javelin, the Czech throwing the spear out to 66.19m with her first throw.
Ethiopia's Tirunesh Dibaba, the defending champion, qualified fastest for the final of the 5,000m in 14:58.48.
Dibaba retained her Olympic 10,000m crown on Friday.