Gatlin, the 2004 Olympic champion who could not defend his crown in Beijing while serving a four-year doping ban, won the 100 -meter final at the US Olympic track and field trials in 9.8 seconds, the third-best time in the world this year.

"I think there's a lot left in the tank," he warned. "I was pleased with my time and the effort."

Gatlin, 30, who won the world 60m indoor crown earlier this year, lowered his own season best from the 9.87 he ran to win last month in Doha and served notice he is aiming at reigning Olympic champion and world record-holder Bolt.

"I don't think I would come back to a sport where I'm OK getting second or third," he said.

Gatlin also said he is ready for any mind games or Bolt's trademark archery-styled theatrics at the start line. "I love entertainment," Gatlin said. "If he wants to tap dance, that's fine. His lane is as long as my lane. I have to worry about me."

Former world champion Gay, who underwent hip surgery last year and only ran two weeks ago, was second in 9.86 with Ryan Bailey third in 9.93 for the last London berth.

LaShawn Merritt, who served a 21-month doping ban but won a legal fight for his chance to compete in London, qualified to defend his 400m crown by winning in 44.12 seconds.

AGENCE FRANCE-PRESSE