(FILES) This file photo taken on August 16, 2008 shows Jamaica's Usain Bolt celebrating after winning the men's 100m final at the "Bird's Nest" National Stadium as part of the 2008 Beijing Olympic Games.
Jamaican sprint legend Usain Bolt labelled himself the underdog on August 1, 2017 as he seeks to round off his glittering individual track career with the defence of his world 100m title this week. / AFP PHOTO / Olivier MORINOLIVIER MORINAFP
