Former world champion Tyson Gay shrugged off damp and cold conditions to power to victory in the 100m at the London Diamond League meeting Friday.
Gay, the second fastest man in history, took advantage of the late withdrawal of Jamaican rival Asafa Powell to clock a respectable 10.03secs into a headwind at Crystal Palace.
The 29-year-old former world champion over 100m and 200m, who is hoping to break the dominance of Usain Bolt and Yohan Blake at the Olympics, finished clear of Ryan Bailey in 10.09sec and Jamaica's Nesta Carter in 10.13sec.
"I feel pretty good with the win. The weather wasn't that bad, it's very important to acclimatise and the weather helps me prepare mentally for the Games," said Gay. "I'm in pretty good shape -- I want that Olympic gold."
Elsewhere Friday, Britain's reigning 5,000m world champion Mo Farah delighted the home crowd with a pulsating win in 13min 6.04sec.
Farah's time was well short of his season's best of 12:56.98 but the 29-year-old was happy to have warmed up for his dream of Olympic glory on home soil with a confident performance.
"One last time at home before the Olympics and the crowd gave me a great boost. It's incredible," said Farah, who finished clear of Australia's Collis Birmingham and Moses Kipsiro of Uganda.
"The conditions were tough but I am used to this weather, so it'll be good for me if it's like this at the Olympics," Farah added.
The other outstanding performance of the night came in the men's 110m hurdles, where American Aries Merritt indicated he will be the man to beat at the Olympics with a superb season's fastest time of 12.93sec.
Merritt, the recent winner of the US Olympic trials and favourite for the gold medal in London, led an American sweep of the top three positions, storming clear of Jason Richardson in 13.06sec and Ryan Wilson in 13.18.
"The conditions were the same for all of us and this will be great preparation for the Olympics if the weather is like this," said Merritt.
"I got here just two days ago so I am a little under the weather as far as my sleeping patterns are concerned. So it's amazing that I am running this well, I can't be more excited.
"I have to do it when it counts -- this means nothing if I can't do it at the Olympics."
China star Liu Xiang pulled out of the final moments before the start, suffering from a bad back.
In-form Puerto Rican Javier Culson scored a psychological blow over British world champion Dai Greene in the 400m hurdles.
Culson, unbeaten over the distance this season, romped home in 47.78secs to equal the season's fastest time he had set in Paris last week with Greene second.
The 27-year-old was always in control, flying out of the blocks to build an unassailable lead before holding Greene, who finished in 48.10sec. Two-time Olympic champion Angelo Taylor of the United States was third in 48.43.
"I would have loved to have won in front of my home crowd but my top-end speed needs to improve," said Greene.
"But I will continue working, I'm running faster than last year. It should be a good Olympic final," he added.
It was a different story for British hopes in the women's 400m hurdles, with Perri Shakes-Drayton recording an impressive win over a strong field which included newly crowned European champion Irina Davydova.
Shakes-Drayton, 23, obliterated her previous personal best of 54.18sec to come home in 53.77sec, equalling the second fastest time of the year set by Davydova, who was second in 54.63sec.
Kaliese Spencer of Jamaica was third while compatriot Melaine Walker, the reigning Olympic champion, was a distant fourth.
Meanwhile Kenyan distance runner Vivian Cheruiyot signalled she will be the woman to beat over 5,000m at the Olympics with a classy victory in 14:48.86, pipping compatriots Mercy Cherono, second with 14:49.26 and Linet Masai, 14:53.93.
"It was important to win because it showed that my preparations are good for the Olympics," said Cheruiyot.
"I am feeling okay. I will now go back to Kenya and work a bit more on my speed and then I will be ready for the Olympics."