London, Aug 11 (IANS): Carmelita Jeter powered the United States 4x100 metre women's quartet to a world record time of 40.82 seconds giving them the gold medal for the first time at the Olympics since 1996.

Jeter screamed down the stretch to cross the finish line here Friday night, pointing the baton at the clock to signal that the previous record was erased from the books.

The US quartet of Tianna Madison, Allyson Felix, Bianca Knight and Carmelita Jeter shattered the previous record of 41.37, which had been set by the German Democratic Republic in 1985 by over half a second Friday night.

Jamaica finished second, while Ukraine won a very creditable bronze medal.

The race had always promised to be fast with Jamaica fielding a team led by 100 metre gold medallist Shelly Ann Fraser-Pryce and including, Sherone Simpson, Veronica Campbell Brown and Kerron Stewart.

Fraser-Pryce may have been Olympic 100 metres champion, but she was always trailing Madison, who flew out of the blocks and handed over a lead to Felix.

The new 200 metre gold medallist, who is having a fantastic Olympics, widened the lead. Knight held the gap and Jeter tore down the final straight raising the baton in triumph as she crossed the line.

The second relay of the night had nine finalists after South Africa had been reinstated after crashing out Thursday. That allowed 'Blade Runner' Oscar Pistorius to make his second Olympic appearance although the battle for the medals did not involve the South Africans.

The Bahamas led after the first two laps before Toby McQuay put the US ahead going into the last 400 metres. That only set the stage for greater drama as Ramon Miller ran the race of his life to close a three-metre gap on US anchor Angelo Taylor.

Miller caught Taylor with 50 metres remaining and strode on to victory. For the Bahamas, who finished fourth four years ago, this was ample compensation.

Meseret Defar from Ethiopia produced the fastest turn of speed in the last 200 metres of the women's 5,000 metres to claim her second Olympic gold medal in the event.

Defar, the gold medal winner in Athens in 2004, was able to out-sprint Vivian Cheruiyot of Kenya and her fellow Ethiopian, Tirunesh Dibaba, to claim gold.

Dibaba went into the race as double gold medal winner at 5,000 and 10,000 metres in Beijing and in good form after winning the 10,000 metres final just a week before.

The race ignited with four and a half laps remaining when Dibaba decided it was time to wind the pace from the average of 75 to 68 seconds per lap to spread out the field and bring the Africans to the fore.

Entering the 400 metres, it was clear the medals were going to be decided between the African runners and Defar had the speed on the final straight while Debaba ran out of gas and was overtaken by Cheruiyot in the closing metres.

Kipyego finished fourth, Gelete Burka fifth and Kibiwot sixth to highlight the dominance of the Ethiopians and Kenyans in the race.

There was a Turkish 1-2 in the women's 1,500 metres as European champion Asli Cakir took gold and Gamze Bulut silver with Maryam Jamal from Bahrain in third.

Renaud Lavillenie of France set a new Olympic record of 5.97 metres to take gold in a thrilling pole vault ahead of Bjorn Otto, who risked everything on one last desperate vault for 6.01 metres, 10 cm higher than his previous best.

Otto's brave bid failed, leaving him to settle for silver, while Raphael Holzdeppe claimed bronze.

Steve Hooker's reign as Olympic pole vault champion came to an end when he failed to clear 5.65 metres. The Australian had struggled for fitness and form in the run up to London and was never able to produce his best.

Russia's Tatyana Lysenko set two new Olympic records on her way to gold in the women's hammer throw.

Lysenko opened her account with a throw of 77.56 metres, to beat the previous record set by Askana Miankova four years ago and bettered that with 78.18 metres in her fifth throw.

Betty Heidler had to wait before she got her bronze medal as officials struggled to find the mark of her fifth throw, which proved to be at 77.13 metres, while Poland's Anita Wlodarczyk took silver when she sent her final throw out to 77.60 metres.

There was no Usain Bolt in the Jamaican team for the 4x100 metre relay, but Yohan Blake, who took silver behind Bolt at both 100 and 200 metres, was in to run the bend before passing to Kemer Bailey-Cole.

Britain also ran under 38 seconds, but were disqualified for an illegal hand over between Daniel Talbot and youngster Adam Gemli who set off too soon and received the baton outside of the zone.

Tyson Gay's last chance of an Olympic medal is intact as the US won their 4x100 semifinal in 37.38 seconds, faster than Jamaica.

Like Bolt, Gay sat out the semi and Saturday's final looks set to produce something very special.

Finally the semifinals for the women's 4x400 relay produced few surprises with the US and Jamaica each winning their respective races with relative ease, while Russia, Ukraine and Britain look destined to fight it out for the bronze medal.