(AP) Olympic champion Ashton Eaton of the United States ran a blistering 400 meters to regain the lead after the first five events of the decathlon Saturday at the world championships.
The world-record holder clocked 46.02 seconds to run the fastest decathlon 400 at a world championships, according to the IAAF.
The grueling two-day event has shaped up as a thrilling battle between two Americans, with 20-year-old Gunnar Nixon only nine points behind Eaton at the end of the first day. But a third American, two-time defending champion and Olympic silver medalist Trey Hardee, dropped out with a hamstring injury.
Hardee developed cramps in his hamstring and missed all three high jump attempts. He was fifth after three events and needed a good performance in the high jump to stay in medal contention.
"It was just one of those things, landed on the pit after my second attempt, my hamstring was grabbing," Hardee said. "I laid there and tried to keep it from cramping up. The third (attempt) came around way too quick."
Nixon, the junior world champion, cleared 7 feet, 1-4 in the high jump to seize a big lead after four events. But Eaton surged back with his fast 400, only 0.39 seconds off his personal best.
Nixon had led Michael Schrader of Germany by 110 points and Eaton by 116 after the high jump.
But the 400 mixed things up again. It's now Eaton with a slim lead of 4,502 points to Nixon's 4,493. Schrader dropped to third with 4,427.
Eaton held the lead after the first three events but cleared only 6-4 in the high jump, his season best nevertheless.
Schrader cleared a personal-best 6-6 1-4. But the high jump belonged to Nixon, who even tried 7-1 1-2 despite already being in the overall lead. However, he failed in all three attempts.
Eaton broke the world record at the U.S. Olympic Trials with a score of 9,039 last year, before confirming that performance with a gold medal at the London Olympics.
The American came to Moscow sitting only 13th place on the world list, with a season-best of 8,291 points for the title at the U.S. nationals.
But he has also set personal bests in five events.
Nixon's top performance is 8,198 points in finishing second to Eaton at the U.S. nationals.
The decathlon ends Sunday after the remaining five events.