London, England (BBC) Olympic and world 400m champion Christine Ohuruogu finished sixth behind winner and arch-rival Sanya Richards at the Bislett Games in Oslo. In only her second 400m of the season, the Briton clocked 51.19 seconds, while American Richards finished in 49.23, the best time in the world this year.

Usain Bolt withdrew from the 100m because of scheduling problems.

In the absence of the Olympic champion and world record holder Bolt, fellow Jamaican Asafa Powell won in 10.07.

Powell, in his second race following ankle surgery, recovered from a poor start to claim victory as he beat Antigua and Barbuda’s Daniel Bailey on the line with the pair sharing the same time.

Britain’s Simeon Williamson finished fourth behind Powell in the 100m ‘A’ final in a time of 10.13.

“I was strong enough,” said Powell. “I had a bad start and my legs were heavy. I tried just to win.”

Ohuruogu’s performance in the second Golden League meeting of the season, but her first serious event, was disappointing.

She admitted she had expected better after recovering from a bug which forced her out of a recent meeting in Italy.

“I thought I was in good shape, so I don’t really know what happened,” said the 25-year-old, who defends her world crown in August. “The extra zip I normally have just wasn’t there.

“I wanted to make a race of it but now I’ll have to wait until Paris (July 17).

“Now I’ll concentrate on next weekend’s world trials in Birmingham where I’m running the 200m.”

Richards’ time in the women’s 400m also tied the Bislett Stadium record, set by Czech Tatjana Kocembova in 1983.

Richards, who took Olympic bronze behind Ohuruogu in Beijing, also won the opening event of the six Golden League meetings in Berlin a fortnight ago.

Shericka Williams, the Olympic silver medallist from Jamaica, finished second in 49.98.

Another British athlete who endured a difficult meet was distance runner Mo Farah.

He has been in promising form so far this season but the task facing him in challenging his African rivals was made clear by his 11th-placed finish in the 5,000m.

Farah produced a time of 13:12.28, the fastest by a European so far this year.

But Olympic champion Kenenisa Bekele took charge of the race over the last two laps to win from James Ckururi and Vincent Chepkok in 13:04.87.

The Dream Mile was won by Deresse Mekonnen of Ethiopia in a world junior record time of 3:49.29.

Elsewhere, Londoner Leevan Yearwood, backed by a very strong following wind, won the 100m ‘B’ race, sharing a time of 10.10 with American Mark Jelks.

And Sheffield’s Richard Strachan won the 400m ‘B’ race in 45.86, with South Africa’s Paralympic gold medallist Oscar Pistorius following him home in a season’s best 47.18.