Olga Kaniskina of Russia celebrates winning the women's 20km race walk final at the IAAF World Championships in Daegu August 31, 2011. [Photo/Agencies]

DAEGU, South Korea - Russia's Olga Kaniskina grimaced her way through downtown Daegu to win the women's 20 kilometres walk title at the world championships for a record third time.

China's Liu Hong took the silver medal ahead of another Russian, Anisya Kirdyapkina, in third.

Kaniskina, who eclipsed compatriot Olimpiada Ivanova's mark with her third title, crossed the line in a time of 1:29.42, eight seconds ahead of Liu.

Kaniskina's win also put an end to Daegu's "curse of the covers", where the official programme's cover stars on each of the previous four days suffered ignominious exits.

Defending pole vault champion Steve Hooker exited without completing a successful jump, Usain Bolt was disqualified from the 100m final, Cuba's Dayron Robles was stripped of gold for bumping in the 110m hurdles and on Tuesday pole vault queen Yelena Isinbayeva failed to clear 4.80.

"Thankfully no one told me about this before the race, they only told me after," Kaniskina laughed at a news conference. "I didn't know about it, but it was a good decision to put me on the cover."

World record holder Vera Sokolova had looked strong at the head of the field but at the hour mark started to suffer and dropped back to finish in 12th place.

With her tortured face slowly relaxing into relief, Kaniskina thrust her arms into the air to celebrate a third consecutive title as legs like bendy straws dragged her over the line.

Kaniskina, also the gold medallist from the 2008 Beijing Olympics, said the conditions were tough in South Korea.

"Compared to Osaka and Berlin this race was very difficult. We were prepared for the hot and humid weather but not for the sun," she added.

"The plan was to go with the group for the first half and then to come out fast. But until the very end of the race I was not sure about my victory. Even in the finish, you cannot be sure about your victory because you still can get a red tag."