Jamaica's Usain Bolt (top right), Yohan Blake (bottom right), Nesta Carter (top left) and Michael Frater pose next to the timing board displaying their new world record in the men's 4x100-meter relay final at the world athletics championships in Daegu, South Korea, yesterday.

In one whirlwind week, Usain Bolt turned the biggest disappointment of his career into another golden show capped with a world record.

After opening with a false start in the 100 meters final last Sunday, Bolt again produced the amazing in his closing race of the world championships - anchoring Jamaica to a world record in the 4x100 relay.

Fittingly, Jamaica's yellow-green-and-black flag was the last one rising into the night over Daegu Stadium, and Bolt spread his giant arms wide to soak in the occasion with all his might. "For me, it was just to go out there fast," Bolt said. "We did just that."

One day after winning gold in the 200, Bolt was devastating down the home stretch of the relay and threw his yellow-clad chest across the line for a time of 37.04 seconds - the only world record in nine days of competition.

There was no more of the performance anxiety that pushed him into a false start in the 100, only a sheer release of power as he coasted down the stretch for an overwhelming win over France and Saint Kitts and Nevis.

The United States was out of it by the last changeover, but no one could have gotten close to a Jamaican team anchored by Bolt.

He got all the help he needed from his three teammates - a lightning start from Nesta Carter and a good handover to Michael Frater before Jamaica's golden duo was up. Yohan Blake, the 100 champion in Bolt's absence, powered through the final bend, with Bolt already getting his giant stride going before he took the baton.

Bolt gritted his teeth over the final meters, crossed the line and threw the glittering purple baton high in the air once he realized their three-year-old record of 37.10 was gone.

On a final day of seven finals, one silver medal also stood out.

Caster Semenya failed to defend her 800 title, faltering late down the finishing straight to allow Mariya Savinova of Russia get the gold. Silver, however, was better than many expected as the South African showed glimpses of her powerful running that made her the dominating athlete over the distance two years ago, before a gender controversy sidelined her for a year.

Allyson Felix added another gold to bring her collection of titles to a women's record eight over four championships. The American ran the second leg of the winning 4x100 relay, one day after getting gold in the 4x400, too.

With Christian Taylor winning the triple jump, it left the US at the top of standings with 12 gold and 25 overall.

Tatyana Lysenko won the women's hammer throw, putting Russia in second place of the standings with nine gold and 19 medals overall.

Britain got some good news ahead of next year's London Olympics, with Mo Farah holding off Bernard Lagat of the US to win the 5,000.

In the morning, Abel Kirui led teammate Vincent Kipruto to yet another 1-2 finish in the men's marathon.