Women's 400m - FINAL

Great Britain's Christine Ohuruogu drew upon her formidable competitive abilitiy to hunt down the pre-event favourite Sanya Richards and add  Olympic gold to her world title in an exhilarating final.

Ohuruogu refused to panic despite entering the home straight more than five metres behind Richards in fourth and timed her run to perfection to strike gold in 49.62.

Jamaica's Shericka Williams finished like a train to clinch a shock silver medal in 49.69 with a distraught Richards having to settle for bronze in 49.93.

For Ohuruogu, 24, it was another demonstration of her enviable ability to peak when in matters. 

At last year's Worlds in Osaka she came from nowhere to take gold and once again she proved the supreme championship competitor.

But while Ohuruogu lay spreadeagled across the track taking in what she had achieved, a crestfallen Richards shed tears of disappointment after failing in her mission to nail the gold.

For Richards it was a case of what might have been. She had dominated 400m running in 2006 and 2007 only to miss out on a spot at the World Championships after falling ill at the trials. Beijing was supposed to be her coronation. It was not to be.

Richards came into the competition boasting an unbeaten record this year, but many seasoned observers believed she has been less convincing this year than in 2006 and 2007.

She may also come to regret her race tactics having adopted a very aggressive approach over the first half of the race and struggled to maintain her form in the latter stages.

For Ohuruogu this was vindication for a diligently prepared season under her coach Lloyd Cowan as she has competed sparingly over the one-lap distance preferring to work on her 200m speed.

Ohuruogu, a former under-19 England netball player who only took up athletics seriously in 2003, was always confident she could land gold despite going into the competition outside of the top ten on the 2008 World Lists with 50.80.

Yet after recording a season's best of 50.14 to win her semi-final she once again loomed as a potential gold medal threat.

In the final her 49.62 winning time was only 0.01 shy of her lifetime best which has recorded at the World Championships in Osaka last year.

Ohuruogu, a former England Under-19 netball player who only started athletics seriously in 2003, admitted: "I know I can perform well when I need to. I may not have a good season but, like at the World Championships, that's what I train all year for. You always have all these dreams about winning, but you never think your dreams will be reality."

Richards, running in lane seven, made the early running and quickly caught the stagger up on Amantle Montsho of Botswana. Russia's Yuliya Guschina from lane six was also prominent but Richards held a sizeable advantage at halfway from Guschina with Ohuruogu hitting the 200m mark in 23.8 holding third or fourth position.

The US champion held had a three metre lead from Guschina entering the home straight with Tatyana Firova of Russia marginally ahead of Ohuruogu, who was at least six metres back on the American.

However, just like at the 2007 World Championships last year, when Ohuruogu's formidable strength told in the latter stages, she sliced through the field down the home straight to hit the front 30m out.

Behind her Williams, who was a distant fifth coming into the final 100m, made a spectacular bid of her own and also surged past the fading Texan.

However, Ohuruogu had too much strength and held on to take gold. Williams picked up a shock silver, Richards bronze.

Guschina headed the Russian challenge finishing fourth in a PB of 50.01 - 0.02 ahead of her compatriot Anastastia Kapachinskaya also in a lifetime best of 50.03. Firova was the third of the Russian trio in sixth (50.11).

The second Jamaican finalist Rosemarie Whyte placed seventh in 50.65 with Montsho, the African champion, in eighth (51.18).

For Williams, a bronze medallist at the Jamaican Championships, it was a remarkable progression.

Aged just 22 and coached by Stephen Francis - like the Olympic 100m champion Shelly-Ann Fraser - she sliced 0.55 from her lifetime best in the final.

It was the slowest winning time for an Olympic 400m final since Monika Zehrt of East Germany won the 1972 title in Munich, not that Ohuruogu will care one jot.

Although despite winning gold in Beijing this may not yet prove the highlight of her Olympic career. In four years' time the Games are coming to her home city of London and that may yet prove an even bigger achievement.

Steve Landells for the IAAF