SCITECHNASA prototype lander explodes in test flight1 of 9OLYMPICS 2012Usain Bolt makes history with 200-meter gold2 of 9U.S.Pennsylvania road crew paints over dead raccoon3 of 9SCITECHMars rover sends color 360-degree photos4 of 9OLYMPICS 2012U.S. women win 3rd straight soccer gold5 of 9POLITICAL HOTSHEETRomney slams Obama's 'misleading' ads6 of 9VIDEOLego art wows crowd7 of 9SPENDING5 new cars to avoid: Consumer Reports8 of 9Complete coverage: Latest from 2012 Olympics9 of 9 August 9, 2012 4:15 PM PRINT TEXT CBSSports.com Official Partner Usain Bolt wins Olympic gold in 200 meters, 1st man to win back-to-back sprint doubles

LONDON - Usain Bolt backed up his billing as a "living legend" by winning the Olympic 200 meters and becoming the first athlete to repeat as double Olympic sprint champion.

"It's what I came here to do. I'm now a legend," Bolt said. "I'm also the greatest athlete to live. I've got nothing left to prove."

Undaunted by the first world record of the Olympic track meet run by 800-meter winner David Rudisha less than an hour before the 200 final, Bolt was not about to be upstaged by anyone.

He dominated his favorite event almost from the starting gun and had enough of a lead to slow down at the line, bring his left index finger to his mouth and signal a "ssssshhh" that was broadcast around the globe.