Usain Bolt jogged and joked his way to his fastest time this year to cruise into the 200 metres final at the Rio Olympics - and then branded his performance "lazy".

The Jamaican, who has already won his third straight 100m gold and is out to do the same in the 200m and 4x100m relay, moved a step closer to an Olympic 'triple triple' as he coasted home in 19.78 seconds.

The 29-year-old got out well and was well ahead on the home straight before easing off and even sharing a chuckle with Andre De Grasse as the pair crossed the line.

De Grasse, the 100m bronze medallist, ran a Canadian record 19.80secs, with Adam Gemili finishing in 20.08s to qualify in third as a fastest qualifier.

On De Grasse, Bolt said: ""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."

The manner of Bolt's run will put fear into his rivals, though. He had so much more in the tank.

He has consistently stated that he is going after his 200m world record of 19.19 here. And his chances of getting it are increasing with ever race.

"I definitely think I can try for the world record," he said.

De Grasse was 14 when Bolt set that mark at the 2009 World Championships in Berlin.

He said: "We were just having fun. I just wanted to go out there and push him to his limits a bit."

Justin Gatlin's medal hopes are over, though, as the two-time drug cheat crashed out, finishing third in his semi-final in 20.13, his time not good enough to go through as a fastest loser.

"My ankle is giving me a lot of problems. I can't run properly and I had a tight turn in lane three," was his explanation.

Bolt's Jamaican team-mate Yohan Blake also went out, meaning, aside from De Grasse, world number one LaShawn Merritt, who has run 19.74 this year, is likely to pose the biggest challenge to Bolt. But he will surely have to blow that time out of the water to take gold, though.

On his run, Gemili said: "I really tightened up. I'm in a lot better shape than 20.08. I was really disappointed seeing that.

"But that's a good thing I suppose that I'm not satisfied with that and I will go and push on."

His team-mate Danny Talbot clocked a personal best 20.25, but it was not enough to go through, the same time as Nethaneel Mitchell-Blake, who also went out.