Unbeatable Bolt signs off with triple-triple

By Nick Mulvenney RIO DE JANEIRO (Reuters) - Usain Bolt drew down the curtain on his brilliant Olympic career by securing a sweep of the sprint titles for a third successive Games when Jamaica successfully defended the 4x100 meters relay crown on Friday. Gay was the last man to beat Bolt in a major championship final - in the 200 meters at the 2007 worlds in Osaka - and despite his disappointment at the disqualification he had nothing but praise for the Jamaican.