Former world record holder Asafa Powell won the 100 metres final at the London grand prix on Friday night in 9.94 seconds running into a slight head wind.
Powell lost his world mark this year to compatriot Usain Bolt who has yet to decide if he will attempt a 100-200 double at next month's Beijing Olympics.
American world champion Tyson Gay, who beat Powell into third place at last year's world championships, was scheduled to run the 100 but withdrew after aggravating a hamstring strain.
"I felt very confident, very relaxed," Commonwealth champion Powell told reporters. "I could definitely have gone a bit quicker. With or without Usain I'm going for the gold medal."
Russian Olympic and world champion Yelena Isinbayeva came desperately close to setting her 13th outdoor world record and 23rd overall when she failed three times at 5.04 metres.
Isinbayeva cleared the bar with her third attempt but brought it down during her descent.
She set her last world record of 5.03 two weeks ago at the Rome Golden League meeting.
Isinbayeva failed with her first two attempts after entering the competition at 4.74. She cleared the third attempt easily and was untroubled with her next two efforts at 4.87 and 4.93.
American champion and record holder Jenny Stuczynski passed at 4.93 and made two unsuccessful attempts at a world record in tandem with Isinbayeva.
"I am very disappointed because I really felt I could jump a world record today," Isinbayeva told reporters.
"It's my third competition in a row and I'm a little bit tired. Beijing is going to be a hard competition and it might be necessary to break a world record to win."
Russia's European champion Andrey Silnov won the men's high jump in a year's best of 2.38 metres.
American champion David Oliver won the 110 metres hurdles in the absence of Cuba's world record holder Dayron Robles who could not get a visa to enter Britain.
"I've got to go away and work on some stuff," Oliver said. "I am feeling very confident, my chances (in Beijing) are as good as anyone else."
World champion Reese Hoffa relegated fellow American and world leader Adam Nelson to second place in the men's shot put. Hoffa's winning put of 21.13 metres was 0.06 ahead of Nelson.
"It was pretty tough out there," Hoffa said. "The distances weren't there tonight but the win will give me a lot of confidence for Beijing."
Jamaica's Commonwealth champion Sherone Simpson won the women's 200 metres in 22.70 seconds. Twice world gold medallist and American champion Allyson Felix faded to fourth place.
"To get a win so close to the Olympics is very good psychologically," Simpson said.
Britain's Olympic heptathlon bronze medallist Kelly Sotherton set a personal best of 6.79 for the long jump assisted by the maximum possible following wind of two metres a second.
"I have had so many issues this year with injury and illness so I am delighted to jump a PB like that," she said. "It is exactly where I need to be for the Olympics."
The 100 metres hurdles was rerun at the end of the original programme because the third barrier was in the wrong position.
Meeting director Jon Ridgeon said officials had made a genuine mistake.
"We asked the athletes if they were happy to rerun the race and they were," he said in a statement.