In so doing, the 30-year-old treble 2007 world champion, defeated the fellow countryman who had claimed early bragging rights in the event this season, Justin Gatlin.

Gatlin, the 2004 Olympic champion who has returned to challenge for sprint honours after serving a four-year doping ban, was second in 9.89.

Meanwhile, Jamaica's double Olympic 100m champion and world record holder, Usain Bolt, earned the right to challenge for the title he lost on a false-start in Daegu two years ago by winning the Jamaican World Championship trials in 9.94, thus booking his place for the Championships, which are due to take place in Moscow from August 10 until 18.

Usain Bolt, a triple champion at the London 2012 Olympics, has secured his place to regain the world 100m title in Moscow this summer

Gay, who had hip surgery in 2011 and was second to Gatlin in last year's US Olympic trials before finishing fourth at London 2012, took control midway through this year's US final in Des Moines.

"It's been five years since I have been the US champion and it feels good to be back on the podium," he said.

"I'm not as sharp as I could be but I'm healthy so that's all that counts."

Gatlin, who beat Bolt by one-hundredth of a second to win in 9.94 in at last month's International Association of Athletics Federations (IAAF) Diamond League meeting in Rome, claimed he was affected by a strained right hamstring.

"It felt good running 9.8 with a bandage on," he said.

Charles Silmon captured the third 100m place on the American team for the World Championships by beatiing Mike Rodgers by two thousandths of a second.

London 2012 silver medallist Yohan Blake missed the trials in Kingston because of a hamstring injury.

But although he will not be able to run in the 200m at Moscow, he qualifies for the 100m as the defending champion.

Bolt recovered from a slow start to catch Nickel Ashmeade at the 50m mark and clocked a time of 9.94s after easing off over the last 10m.

The sub-10 second run was the 35th of his career and the 26-year-old said: "It was good to win... I'm not too worried about the time as I have one solid month to work on getting ready for Russia."

Asked about Gay's impressive run, Bolt said: "The trials are always [about making] the team, because it's at the [World] Championships [where] it really matters.

"I had ran 9.63, 9.58, so I have set the (Worlds qualifying) standard already."

Kemar Bailey-Cole took second place in 9.98, while Ashmeade, who made the 200m final at the 2011 World Championships, was third in 9.99.

But former world record holder Asafa Powell, troubled by hamstring problems this season, failed to fire in his third straight race in two nights, and could only finish seventh in 10.22.

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