DAEGU (AP) -- One of the most anticipated races of the world championships turned into one of the most controversial with Olympic champion Dayron Robles accused of pulling rival Liu Xiang out of the hunt for gold in the 110-meter hurdles.

The field judges disqualified the Cuban, which instead gave the title to Jason Richardson. The American profited from Liu's tangle to sneak across the line in second. The Cubans have lodged an appeal.

``When I approached the ninth hurdle, Robles pulled me. It made me slow down,'' said Liu, who had finished third. ``At first, I thought I would be the champion or at least second. But Robles pulled me.''

David Oliver of the United States was a pre-race favorite but crossed the line in fifth.

Oliver was out of the final between the three fastest men in history from the second of 10 hurdles. The Cuban crossed the line in 13.14 seconds, followed by Richardson in 13.16 and the fast slowing Liu in 13.27.

The Americans won a sprint title for sure when Carmelita Jeter came back from behind to win the 100 ahead of Jamaican veteran Veronica Campbell-Brown. Kelly-Ann Baptiste of Trinidad and Tobago took bronze.

The United States was also expected to top the women's 400, but it was Amantle Montsho who gave Botswana its first medal at a world championship, and a gold one to start out with.

Allyson Felix, a three-time world champion in the 200, was even with Montsho as they entered the final straight but couldn't overtake her down the stretch. Felix was looking for a 200-400 double at the worlds and two relay titles as well.

Montsho won in a national record time of 49.56 seconds. Felix was second in 49.59 and Anastasiya Kapachinskaya of Russia was third in 50.24.

Defending champion Sanya Richards-Ross of the United States finished seventh in 51.32.

Also, Pawel Wojciechowski of Poland won gold the pole vault, clearing 5.90 meters and beating Lazaro Borges of Cuba for silver on a countback of fewer missed attempts.

Favorite Renaud Lavillenie of France took bronze with a height of 5.85.