Tyson Gay handed world and Olympic champion Usain Bolt his first defeat in 15 100m finals at the Diamond League Friday.
With the two fastest men in the world facing each other down, Gay emerged victorious in a stadium-record time of 9.84 with Bolt second in 9.97.
Gay told reporters: "I know Usain Bolt is not in his best shape, but I'm still happy with the victory.
"My body worked well today, I was excited and motivated. The start was OK but I must admit I was surprised not seeing Usain in front after half the race."
Bolt said: "It was an alright performance, it wasn't one of my best. I need to work on my strength, my strength is really low. It let me down in the first 30 metres and Tyson was in the better shape so he won the race."
Bolt, who has been troubled by an Achilles injury, has said he is treating this year as an "off year."
Organisers had hoped for a repeat of last year's world championship final only for ex-world record holder Asafa Powell to pull out earlier this week with a back injury.
HEEL INJURY
In other top-flight action, Sweden's ace triple jumper Christian Olsson showed welcome signs of a return to form after a heel injury which kept him out of last week's European championships in Barcelona.
Former world and Olympic champion, Olsson was delighted with his second place to Teddy Tamgho of France and a season-best of 17.32.
He told Reuters: "Second place, four centimetre behind number one. He's probably number one in the world even though he didn't win the European championship. I must be pleased with that."
Croatia's European high jump champion Blanka Vlasic defied fatigue to claim her fifth straight Diamond League victory over Chaunte Lowe of the U.S. who had to be content with second again.
"I was so empty after the Europeans," said Vlasic. "I expected to be more fresh but I guess I wasted too much energy." Local favourite and European silver medallist Emma Green came third.
American sprinter Allyson Felix was critical of her own performance, despite winning the women's 200m. The world champion said: "It didn't go as well as I would have wanted it to, I wanted to execute a little better.
"I think I floated coming off the curve and I just didn't execute the last 100."
Dariya Klishina of Russia won the women's long jump in 6.78, beating Brittney Reese of the US by three centimetres.
"I missed Barcelona so this is something special for me, the first Diamond League win of my career," said Klishina.
