BEIJING (AP) — After a two-year absence, Ashton Eaton needed only 10.23 seconds to establish himself again as the favorite to win the decathlon at the world championships.

That's how long it took the American to run the 100 meters in a championship decathlon record on Friday at the start of the two-day competition.

Eaton immediately followed that up by winning the long jump with a leap of 7.88 meters, and then had good showings in the shot put and high jump to put him in a strong position after four of 10 events.

Instead of a rusty returnee to competition, the Olympic champion immediately took control. He leads with 3,643 points, 56 more than Damian Warner of Canada.

Although Eaton is back on the track, American teammate Trey Hardee, a two-time world champion, is out with a lower back injury he sustained in the long jump.

Instead of Hardee, Warner is likely to be Eaton's toughest rival. After four events, Kurt Felix of Grenada was third with 3,518 points.

Last season, Eaton took a break from the most bruising and draining competition in the sport and centered on experimenting with the 400 hurdles — which is not even a decathlon discipline. He did not complete a decathlon this year before coming to Beijing.

For the home fans, all the excitement came early as China finally earned its first gold medal with Liu Hong leading a 1-2 finish ahead of teammate Lu Xiuzhi in the 20-kilometer walk.

Despite the early-morning start, tens of thousands of home fans packed the stands in the Bird's Nest to welcome the walkers and cheer their first victory as the championships headed into the final weekend.

China has come close before, but three silvers have left the crowds disappointed. There never was any doubt they would go one better in the walk.

The talk of a clean sweep for the Americans in the 100 hurdles was silenced by an early crash from 2008 Olympic champion Dawn Harper-Nelson. That was followed by a false start and disqualification by Keni Harrison in the next semifinal heat.

Sharika Nelvis and Brianna Rollins did make it through to the final, as did Jamaican sisters Danielle and Shermaine Williams.

In other finals later Friday, Dafne Schippers of the Netherlands will be looking to break the stranglehold of Jamaica on the sprints in the women's 200. Usain Bolt won both the men's 100 and 200 and Shelly-Ann Fraser-Pryce took the women's 100. Schippers took silver in the 100 and Fraser-Pryce is not running the longer distance this year.

Her task was made easier when Allyson Felix skipped her favorite event to concentrate on the 400 instead, where she won a ninth world championship gold medal on Thursday.

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Raf Casert can be followed on Twitter at http://www.twitter.com/rcasert