MOSCOW (AP) — The United States is looking at a possible sweep in the 110-meter hurdles at the world championships after its three top runners reached the semifinals Sunday.

Olympic gold medalist Aries Merritt, defending champion Jason Richardson and the season's fastest man, David Oliver, all won their heats.

Merritt and Richardson combined for a 1-2 finish at last year's London Olympic.

"I wouldn't mind if we swept up the hurdles," Richardson said, anticipating that with Ryan Wilson also through, they could even go 1-2-3-4.

"I'm coming on this team with an amazing group of athletes. Aries is formidable with the world record. David, former American record holder. Of course, Ryan, who's a veteran of the game," Richardson said. "Feel bad for fourth place, but, hey, things happen."

Hansle Parchment of Jamaica, a bronze medalist at the London Olympics, finished fifth in his heat but made it through as the one of the fastest losers.

In the decathlon, Olympic champion Ashton Eaton is closing in on his first world title, holding 6,280-6,161 edge of Michael Schrader of Germany with three of the 10 events remaining.

American newcomer Gunnar Nixon went into the second day challenging for the lead, but quickly fell back into fifth position after the 110 hurdles and the discus throw.

While all eyes will be Usain Bolt in the 100 meters later Sunday, the women sprinters started their qualifying heats in the morning humidity at a near-empty Luzhniki Stadium.

Most favorites never pushed themselves in advancing to the semifinals, but American runner English Gardner went well under 11 seconds in 10.92 to be the top qualifier.

"We've trained through a lot of meets, and finally, like I always say, the lion got let out of the cage and I just went out there and had some fun," Gardner said.

Defending champion Carmelita Jeter, Alexandria Anderson and Octavious Freeman made sure all four Americans advanced.

Kerron Stewart and two-time Olympic champion Shelly-Ann Fraser-Pryce led the Jamaican contingent of four into the semifinals, setting up the next chapter of the Jamaican-U.S. sprint rivalry.

Blessing Okagbare of Nigeria could be a spoiler, however, after a sterling season in which she beat some of the best in both sprints and the long jump, where she could well medal later Sunday.

The other finals on Day 2 are the men's 20-kilometer walk, where host Russia is favored to get a first gold, the women's discus throw and the women's 10,000.