Reigning world champion Yohan Blake and 2008 Olympic champion Shelly-Ann Fraser-Pryce, both of Jamaica, won 100-meter titles on Saturday at the Diamond League athletics meet in New York.
The day also saw the triumphant return of Tyson Gay in a B-level 100 race, a romp by 800m world champion David Rudisha and another failure to reach an Olympic time standard for South African Oscar Pistorius.
Blake battled back to edge Trinidad and Tobago's Keston Bledman at the line and win in 9.90 seconds, with American Michael Rodgers third in 9.99 and 2008 Olympic runner-up Richard Thompson fourth in 10.09.
The runners were aided by a legal tailwind of 0.7m/sec.
Last year in South Korea, Blake became the youngest world 100m champion by winning the final after world record-holder and reigning Olympic champion Usain Bolt was disqualified for a false start.
Former world champion Gay, running into a headwind of 1.5m/sec, prevailed in 10.00secs with Jamaican duo Kemar Bailey Cole and Jason Young second and third in 10.30sec in a photo-finish.
The 29-year-old American had not raced in nearly a year after hip surgery last year, but served notice he will be a contender to earn an Olympic berth at the US trials later this month in Eugene, Oregon.
"For my first race in a while, that's not a bad time," Gay said. "It feels good to be back."
Fraser-Pryce, the 2009 world champion and defending Olympic champion, grabbed the lead early and won in 10.92 seconds, her best time so far this year coming three weeks before Jamaica's Olympic trials.
"I came out here just to execute a good race. Everything went right," said Fraser-Pryce. "This was very important going into my national championship."
American Tianna Madison was second in a personal-best 10.97 with Carmelita Jeter, whose 10.81 is this year's world best, third in 11.05, only .02 ahead of fellow American Allyson Felix, a three-time world champion and two-time Olympic 200m runner-up.
Kenyan's world record-holder Rudisha cruised to victory in 1:41.74, the fastest time in the world this year. Kenyan Alfred Kirwa Yego, the 2007 world champion, was a distant second in 1:44.49.
"It was a fast time," Rudisha said. "It felt good for my first time in the United States. I'm in great shape and I'm expecting to perform well in London."
Two-time world indoor champion and last year's world outdoor runner-up Abubaker Kaki of Sudan pulled up in the first turn of the last lap and did not finish.
Dominican teen Luguelin Santos won the men's 400 in 45.24, .06 ahead of runner-up Jeremy Wariner, the 2004 Olympic champion, with Chris Brown of Bahamas third in 45.35 in a strong field.
"That was the whole thing about the race, just be the winner," Santos said.
South African 'Blade Runner' Oscar Pistorius, the four-time Paralympic gold medalist trying to run 45.30 to be considered for an Olympic berth at 400m, was last in 46.14 but confident he could meet the standard by the end of June.
"I have another two races by the end of the month," Pistorius said. "I'm sure I can put it together."
World champion Jason Richardson took the 110 hurdles, holding his patience through three false starts before winning in 13.18. Fellow American Jeff Porter was second in a personal-best 13.26 with Cuban Orlando Ortega third in 13.35, .02 ahead of 2008 Olympic bronze medalist David Oliver of the United States.
American Bernard Lagat won the men's 1,500 in 3:34.63, with Djibouti's Ayanleh Souleiman second, .10 of a second back, and American David Torrence third in 3:35.48.
"I'm so happy. I wanted to win so bad," Lagat said. "It tells me that I'm ready to run fast. But I feel I'm rusty a little bit. I need to get it going a little faster now heading into the trials."
Ethiopian Fantu Magiso celebrated her 20th birthday by winning the women's 800 in a national-record 1:57.48 and American T'Erea Brown won the 400 hurdles in 54.85 seconds, edging Jamaica's Kaliese Spencer by .06 of a second.
South Africa's Sunette Viljoen won the women's javelin with a throw of 69.35m, the longest distance in the world this year.
New Zealand's Valerie Adams, a three-time world champion and the reigning Olympic champion, broke her own meet record to win the women's shot put with an effort of 20.60m.