Clay, 24, with decathlon bests in the discus (52.10), pole vault (5.10) and javelin (68.36), compiled 8660 points — 178 more than his previous top score.
Pappas was second with 8517 to earn a berth in Athens, but he was 267 points off his best, set at last year's U.S. championships.
Clay, lured to the event as a teenager by 2000 Olympic bronze medalist Chris Huffins, draped himself in a Hawaiian flag to celebrate his triumph in his first decathlon of the season. His score was third-best in the world this year behind Roman Sebrle's 8842 and Pappas' 8732 in Götzis, Austria, on May 30. Only an exhaustingly slow 5 minutes, 6.18 seconds in the heat of Sacramento kept Clay from an even more impressive score.
Sacramento 2004 - results