The Jamaican seven-times gold medalist exchanged friendly smiles with first-time Olympian De Grasse as they charged toward the line to finish the heat in 19.78 and 19.8 seconds respectively.

"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," said Bolt, who is aiming to win his third triple batch of Olympic gold medals in Rio.

"I saw that he got a national record actually, so he means business," said the Jamaican, who turns 30 on Sunday, the final day of what he has said will be his last Olympics.

It would be the first time in history a runner has collected the "triple-triple", a goal so audacious that no athlete even attempted it before Bolt, who won the 100m on Sunday and told reporters he might be able to beat his world record time of 19.19 seconds in the 200m final on Thursday.

"I definitely think I can try for the world record, I definitely feel that," Bolt said. "I need to run efficiently and get into the straight and run the perfect race."

But several factors would have to fall in to place for that to happen, he said, including a draw of the sixth or seventh lanes, to take advantage of the more gradual curve on the outside of the track.

One of Bolt's main rivals, American Justin Gatlin, who took silver in the 100m, will not be in the race on Thursday. The 34-year-old was being eliminated by a third-place 20.13 in his heat.

"I wasn't truly surprised, I thought he actually made it but I could tell from the 100m he was slowing down," Bolt said.

Overall, the ebullient sprinter remained his upbeat self as he joked with reporters.

"I'm happy, you know what I mean? But I don’t get over-confident," said Bolt, who has said this will be his final Olympics.

"I remember that I still have to run and execute right, so I'm focused on getting it done."

(reuters.com)