Galen Rupp, racing on his home town track at Eugene, Oregon, set a United States record of 26min 44.36sec in winning the 10,000 metres on the first day of the International Association of Athletics Federations Diamond League meeting.
The Olympic silver medallist, who trains with Britain's Mo Farah in Oregon under the direction of coach Alberto Salazar, bettered his own mark of 26.48.00 as he produced the fastest time run so far this year to finish ahead of a field which included five other sub-27min runners.
Kenya's world bronze medallist Paul Tanui was second in a personal best of 26:49.41, ahead of two other Kenyans who set personal bests, Bedan Karoki with 26:52.36 and Stephen Sambu 26:54.61.
While Rupp revelled on home ground, his compatriot Brittney Reese, who has won six consecutive global titles since 2009, suffered a surprise defeat in a hugely competitive long jump won by Serbia's Ivana Spanovic in a national record and 2014 world best of 6.88 metres with her sixth and last effort.
Spanovic thus earned victory over Russia's double European indoor champion Darya Klishina, who had also managed 6.88m in the third round.
The Serbian took maximum Diamond League points thanks to a superior second best jump to Klishina's, 6.86 to 6.81.
Reese, making her main international debut of the season, was only two centimetres adrift of the winner with 6.86, but could do no better than fourth place behind France's world indoor champion Eloyse Lesueur, who managed 6.87.
While Reese, who opened her last Diamond League season with an event record of 7.25, struggled to make an impact, there was no such problem for world and Olympic discus champion Sandra Perkovic.
The Croatian, unbeaten in last year's Diamond League meetings and whose debut in the competition this season at Shanghai produced an effort of 70.52m, the furthest thrown this year, finished more than seven metres clear with a meeting record of 69.32m on her final attempt.
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