Rudisha wins men's 800m

Daegu - World record holder David Rudisha of Kenya won gold in the men's 800 metres at the world championships on Tuesday with a dominant display of front running.

The rangy Rudisha, who broke the world record twice in a week in 2010, took the title in Daegu in a time of 1:43.91 ahead of Abubaker Kaki of Sudan.

The bronze medal went to Russian Yuriy Borzakovskiy.

Rudisha is unbeaten over the distance in two years, his last loss coming when he failed to qualify for the 2009 world championship final in Berlin.

Women's pole vault world record holder Yelena Isinbayeva went out of her event when she failed to clear 4.80 metres.

The Russian Olympic gold medallist had been favourite to regain the world title she won in 2005 and 2007 but lost two years ago, but was far from her best.

In the men's 400m hurdles semifinals, injured defending world champion Kerron Clement slumped out of the competition, finishing slowest out of all 24 runners in the semifinals, while South Africans Cornel Fredericks and LJ van Zyl both qualified for the final.

American Clement, also the 2008 Olympics silver medallist, timed 52.11sec, more than three seconds slower than quickest qualifier Javier Culson of Puerto Rico (48.52sec).

"I have had a groin injury for the past couple of months. I tried to push through the pain in the first round. In this semifinal the pain came strong after the third hurdle and then I could not continue my pace," said Clement.

"But my spirits are high, the most important now is to stay healthy again next season."

Also through to Thursday's final were Dai Greene of Britain and US pair Angelo Taylor, the Olympic champion, and Bershawn Jackson, who took bronze at the Beijing Games.

In the heptathlon, Russian Tatyana Chernova plucked the title from Jessica Ennis after a woeful display of javelin throwing by the Briton.

After two gruelling days of the seven-discipline event, Chernova amassed 6 880 points, with Ennis taking silver (6 751pts) and Germany's Jennifer Oeser claiming bronze (6 572).

Chernova timed 13.32sec in the 100m hurdles, managed bests of 1.83m and 14.17m in the high jump and shot put, clocked 23.50sec in the 200m, leapt a best of 6.61m in the long jump, and crucially threw the javelin to 52.95m.

That javelin performance allowed Chernova to leapfrog Ennis, who only managed a poor best of 39.95m, going into the final event, the 800m.

The points difference Chernova accrued with the crushing javelin difference handed her a 9sec cushion and knowledge that only a catastrophe would stop her claiming gold in the tough two-day, multi-discipline event.

Ennis predictably bolted out in the 800m and completed the first lap in a fast 1:00.88, but Chernova, whose personal best is 2sec quicker than the Briton's, sat comfortably in second tracking her.

Ennis was caught by Poland's Karolina Tyminska with 200m to go, and Chernova produced a spurt to finish on the Briton's spikes and guarantee a new world champion.

Germany's Oeser won a four-way battle for the final spot on the podium, finishing just 28pts ahead of Tyminska, with Ukraine's Natallia Dobrynska just a further 5pts adrift.