BEIJING -- Usain Bolt is perfect yet again.
Dispelling two years of injury doubts, the Jamaican won three sprint gold medals this week for an overall world championship record of 11. The last of them came Saturday when he anchored the 4x100-meter relay team with free-flowing, giant strides that have made him an icon for the sport.
Behind him, the United States was far back in second place. But Justin Gatlin, who had been unbeaten in two seasons of sprinting, lost the chance for a third silver when the American team was disqualified for a bad exchange on the anchor leg.
"I saw the mess after 300 meters and was happy we were not in it," Bolt said.
To the delight of the tens of thousands of fans in the Bird's Nest, China moved up to silver and Canada took bronze.
It was Bolt's third sprint triple in a row, starting at the London Olympics and continuing through the 2013 worlds in Moscow, and fifth overall.
The Americans got solace from Ashton Eaton's world-record performance in the decathlon. The Olympic champion beat his own mark with a stirring run in the closing 1,500 meters.
For the Jamaicans, the women's 4x100 relay team made Saturday's sprint party complete.
They brought a smile to Bolt's face ahead of his race when they won gold, beating the U.S. team with a championship record and the second fastest time in history at 41.07. It also was the second gold for Shelly-Ann Fraser-Pryce, whose performances were again as flashy as her green hairdo.
The Jamaican win denied Allyson Felix a 10th world title, but the American veteran will get another chance in Sunday's 4x400 relay.
"This is not the end for me," Felix said.
Veronica Campbell-Brown, however, got another sprint relay gold 11 years after winning the 4x100 title at the 2004 Athens Olympics. At 33, she was the leadoff runner.
Earlier, Mo Farah joined Bolt with a third straight double in individual events at global competitions since winning the 5,000 and 10,000 meters at the London Olympics. After defending the 10,000 world title on the opening day last weekend, he had a relatively easy race in the 5,000 on Saturday.
Hanging back in last place for the first two kilometers, Farah then quickly moved up. When Caleb Ndiku sought to sprint away over the last lap, Farah kept the Kenyan in check and beat him in the finishing straight.
"It felt amazing," Farah said. "Incredible."
Ever since the 2012 Olympics, Farah has been unbeatable over the long distance races and has six major gold medals to show for it. Only Bolt has done similar.
On a road just outside the Bird's Nest, Matej Toth of Slovakia won the longest event at the championships, taking gold in the 50-kilometer walk in 3:40:32.
In other events, Russian high jumper Maria Kuchina took gold ahead of Blanka Vlasic of Croatia, Marina Arzamasova of Belarus won the 800 and Piotr Malachowski won the discus, giving Poland a third gold in the throwing events.