Beijing - Sprint rivals Usain Bolt and Justin Gatlin sailed into the semi-finals of the men's 100 metres at the world championships on Saturday.
Boos rang round a packed Bird's Nest in Beijing when Gatlin, who has served two doping bans, was introduced to the crowd over the loudspeaker.
But the 33-year-old American roared home in the fastest time of 9.83 seconds while defending champion Bolt, greeted with whoops at the stadium in which he took the world by storm at the 2008 Olympics, cruised home in a very comfortable 9.96.
"Overall it was good," said Bolt, greeted as a returning hero when he was introduced before his heat and nodding his head to a Bob Marley tune pumping around the iconic arena. "I wasn't trying to run fast. I was just trying to do as much as possible to get through the round.
"I know tomorrow, just watching the guys and how fast they're running, the semi-finals are going to be pretty fast," added the towering Jamaican, who celebrated his 29th birthday on Friday. "I didn't need to worry. I was just trying to execute and save as much energy as possible."
Gatlin, 33, powered through to the line and pulled a pistol salute to television cameras after sending a clear message to his rivals.
"I was on the bus today and I thought about what time I was going to run and I was blank in my mind," said Gatlin, who has clocked the quickest time in the world this year of 9.74. "When I get on the line I just try to execute as best I can.
"I just give it my all. I'm not going to lie. When it gets to the finals I'm going to go out there and execute my race and see what happens."
Such has been Bolt's complete dominance of sprinting since 2008 that astonishingly the only time he has failed to land a major title was when he was disqualified for a false start in the 100m in Daegu four years ago.- Symbolic struggle -
With allegations of widespread doping engulfing athletics, his showdown with the sport's pantomime villain Gatlin is being viewed by some as a symbolic struggle of light versus dark.
Asked about Bolt shutting his race down at around 60 metres and coasting to the finish, Gatlin shrugged: "You look at Bolt, he did the same thing in 2012 (at the London Olympics). He ran kind of slow in the first round, picked up in the semis and crushed it in the final."
Fellow American Trayvon Bromell also put down a marker as the 20-year-old clearly eased up in clocking 9.91, having gone 9.84 earlier this season.
"My start really wasn't that good but it got me out and I just wanted to stay focused and not tighten up," he said. "I was cruising at the end."
He will be joined in the semi-finals by teammates Tyson Gay - the double 2007 world sprint champion - and Mike Rodgers, both of whom have also served doping bans.
"I was just trying to get the cobwebs out," said Gay after posting an ordinary time of 10.11. "It's been a long time (to compete at a world championships). It felt good."
Frenchman Jimmy Vicaut stormed home in 9.92 with Canadian hope Andre de Grasse, 20, timing 9.99 behind him in their heat.
Jamaican Asafa Powell, the self-proclaimed "king of the sub-10", clocked 9.95 in winning the opening of the seven heats, China's Bingtian Su nabbing second in 10.03 to the public's delight.
It was the 92nd time Powell, who served a six-month ban for doping after a positive test saw him miss the 2013 worlds in Moscow, has dipped under the once-mythical 10 second barrier.
The semi-finals and final are scheduled for the evening session on Sunday.