DAEGU, South Korea (AP) -- With a brisk 20-kilometer walk through the morning sunshine, Olympic champion Olga Kaniskina won her third straight world title to push Russia to the top of the overall medals standings halfway through the championships.

After the failures of champions like Usain Bolt and pole vaulter Yelena Isinbayeva, Kaniskina went out strong and never faltered as she continued her domination of athletics' quirky event.

Liu Hong of China took silver and Russian teammate Anisya Kirdyapkina added bronze in the only race on Wednesday's program.

Victory gave Russia 10 medals overall and four gold. The United States also has four gold medals, but nine overall.

Although Kaniskina won by a big margin, she was worried until the end about disqualification for having her walk turn into a run when both feet lift off the ground.

“Even in the finish, you cannot be sure about your victory because you still can get a red tag,” Kaniskina said.

Disqualification has been too much of a story already during the first half of the championships. Bolt false started in the final of the marquee 100 meters and saw his chance for a third golden triple in as many global championships evaporate when he was shown the red card.

Compounding that, world-record holder and Olympic champion Dayron Robles was disqualified for obstructing rival Liu Xiang in the 110 hurdles final, handing the title to American outsider Jason Richardson.

Until Wednesday, every star that organizers put on the front of their official program, from Bolt to Robles to sixth-place finisher Isinbayeva, met with debacle. It was only Kaniskina to break the “curse of the cover” as it became known.

“I wasn't even aware that I was on the cover today,” Kaniskina said. “I'd like to thank everyone for not telling me about it before the race.”

Bolt seemed a certainty for a sprint double. Now that possibility is open only to Carmelita Jeter of the United States.

She got the better of Veronica Campbell-Brown in the women's 100, but during Thursday's 200 heats, Jeter moves into the territory long dominated by the Jamaican at the Olympics and by Allyson Felix at the world championships.

Felix was seeking a 400-200 double but a loss to Amantle Montsho of Botswana in the 400 has forced the American to focus on defending the 200 title she has already won three times. She is also slated to run the two relay races over the weekend.

Bolt, too, still has a chance of a double. After the blow in the 100, he has his best event coming up in the 200. He will start running again on Friday in those heats, with the 4x100 relay final the very last race of the championships on Sunday.

When it comes to doubles, Kenyan runner Vivian Cheruiyot is going for the long-distance one in Friday's 5,000. She already won the 10,000.

After winning the first six available medals on the opening day, 800 champion David Rudisha and Cheruiyot have added to the haul that has pushed the east African country into third place with eight medals, three of which are gold.

Kenya should certainly rake in more during Thursday's men's steeplechase and Saturday's 1,500.

“At the moment,” Rudisha said, “we Kenyans are very happy to see our flag rising so often.”