Justin Gatlin set the fastest time, but there was an ominous effortlessness about the way a “sluggish” Usain Bolt progressed through the first round of the men's 100 meters at the Rio Olympics on Saturday. Bolt made his first appearance on the track at the Olympic Stadium as he seeks to become the first man to win three successive Olympic 100m crowns as part of a unique “triple triple” along with the 200m and 4x100m relay.

And, despite a slow start and easing off for the final 20 meters or so, the Jamaican still won his first-round heat in a time of 10.07 seconds to move onto the semifinals on Sunday evening. The 29-year-old was not happy, though, suggesting he was “kinda sluggish” because of the early time on the race, just after midday in Rio.

“I think because it's the morning,” he said afterward. “I'm not used to running this early in the morning. It wasn't the best start. I felt kind of slow. Hopefully tomorrow I'll come out and I'll feel much better, much smoother."

Usain Bolt Usain Bolt eases up as he wins his heat in the first round of the men's 100m at the Rio Olympics. Photo: Getty Images

Encouragingly for Bolt, he insisted that there were no ill effects from a hamstring injury that caused him to miss the Jamaican trials last month. And the scenario is already similar to the World Championships in Beijing a year ago. Then, as now, Bolt arrived having had a season disrupted by injury and had been outshone by his chief rival Gatlin both during the season and in the preliminary rounds at the championship itself.

Gatlin has set the two fastest times in the world this year and went quickest in the first round of the Olympics as he began his quest to add to the gold he took in the 100m back in 2004. In not nearly as leisurely a style as Bolt, the American set a time of 10.01.

“I felt good,” the 34-year-old said afterward. “I think I'm going to have to run a bit faster [than his 9.80 season best] to win this medal. The crowd was great. It's the culture to party. It's excitement. We're going to bring that to the track."

Having wilted under the pressure when going up against Bolt in the final of the 2015 World Championships, Gatlin has repeatedly tried to portray a relaxed mindset this time around in Rio. Yet, despite continuing to set blistering times since returning to the sport in 2010 following a four-year doping ban, the fact remains that in eight races in which he has faced off with Bolt Gatlin has come out on top just once, in a Diamond League meeting in Rome in 2013.

The two will be kept apart in the semifinals, with Bolt going in the second semifinal and Gatlin in the third. Bolt will be joined by 2015 World bronze medalist Andre De Grasse and the man who finished second to Gatlin in the U.S. trials, Trayvon Bromell. Gatlin, meanwhile, will line up with Bolt's compatriot Yohan Blake. The Jamaican finished second behind Bolt in the 2012 Olympics final and is looking to get back to form after a run of injuries in recent years.

In the first semifinal, African champion Ben Youssef Meite will aim to back up his time of 10.03 in the first round, while Frenchman Jimmy Vicaut, who ran 9.86 earlier this year, will be aiming for a marked improvement on the 10.19 he set to only just scrape through to the semifinals.

Prediction: The semifinals will of course tell us more, but so far the script is ominously similar to last year. Bolt is a man who shows up when he really matters and it is difficult to see him not doing the same again in the final. Gatlin is not quite as fast as last year going into the World Championships final, while Bolt looks sharper. The Jamaican has time and again shown an ability to deliver under pressure and, if he can improve his start, has to be strongly favored to claim a remarkable third successive gold. Behind the two favorites, Johan Blake has the experience and looked to be in the kind of shape in the first round that could see him pick up another medal.

Winner: Usain Bolt

Olympic Men's 100m Final Betting Odds

Usain Bolt: 4/11

Justin Gatlin: 5/2

Yohan Blake: 14/1

Trayvon Bromell: 25/1

Andre de Grasse: 33/1

Jimmy Vicaut: 66/1