Tyson Gay overcame Olympic bronze medallist Justin Gatlin’s quicker start and sped to the year’s fastest 100 metres, clocking 9.75 seconds at the US trials for the world championships.

Fully fit for the first time in years, Gay took control mid-race with a dominant run to equal the 10th fastest 100m of all time. Gatlin finished second in 9.89 seconds in the race at Des Moines, Iowa.

“It’s been five years since I have been the US champion and it feels good to be back on the podium,” said Gay, beset by injuries since winning both sprint titles at the 2007 world championships.

“I’m not as sharp as I could be but I’m healthy so that’s all that counts,” said Gay, who ran another 9.75, this one wind-assisted, in the semi-finals.

Gatlin, who surprised Jamaican world record holder Usain Bolt in Rome earlier in the month, said he was affected by a strained right hamstring.

“It felt good running 9.8 with a bandage on,” said the 2004 Olympic gold medallist who narrowly edged Gay for the bronze medal at last summer’s London Games.

Charles Silmon grabbed the third spot on the US team for the Aug. 10-18 world championships by edging Mike Rodgers by two thousandths of a second. Silmon ran 9.972 and Rodgers 9.974.

Collegiate champion English Gardner came on strong to win the women’s 100 in another year-best time, 10.85 seconds, and Olympian Sharon Day delivered the top heptathlon score of the season, 6,550 points.

Gardner, now coached by John Smith, edged Octavious Freeman (10.87) with Alexandria Anderson grabbing third (10.91).

Haitian-born Barbara Pierre struggled to finish fifth after setting the world lead of 10.85 in the semi-finals that Gardner equalled.

Beijing Olympic gold medallist Lashawn Merritt led 400m qualifying in 44.36 seconds but London winner Sanya Richards-Ross, hampered by toe surgery, barely slipped into the women’s final as the next-to-last qualifier.

She ran 51.53 with Francena McCorory the leader at 50.53.