Rudisha whimsically entertained the prospect of a showdown over 400 meters against Bolt, who used to run that distance but abandoned it because it was too much of a grind.
"I think if I train, I can take Rudisha over 400 meters," Bolt said.
Elsewhere Thursday, Americans went 1-2 in the decathlon (Ashton Eaton and Trey Hardee) and the triple jump (Christian Taylor and Will Claye), raising the U.S. track and field total with three days to go to 24 medals, one more than the total in Beijing.
Jamaica is tied for second with nine track medals after Thursday — four from Bolt and Blake.
When they returned to collect their prizes and hear their national anthem once again, Bolt did his now-customary leap up to the top step of the podium. He kissed his medal, then bit it.
Before Thursday's victory, Bolt was wearing a backward yellow baseball cap with a black interlocking "UB," and he added a special British-flavored touch to all his prerace preening, holding a hand aloft for a simple royal wave. Then he curled his arms, one at a time, pretending he was lifting barbells, and looked right at a TV camera.
As ever, ready for his close-up.
Later in the evening, as his news conference ended — after he noted that his medals are "in a safe deposit box with some armed men around them," and talked about making a terrific winger for a soccer team — Bolt spread his arms wide and closed the session with this pronouncement:
"I am now a living legend. Bask in my glory."
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