Usain Bolt can become the first man to claim a second successive 100m-200m Olympic Games double on Thursday with the Jamaican superstar confidently predicting his own 200m world record could fall. Bolt retained his 100 metres crown on Sunday and looked to be in ominous form once again on Wednesday when he strolled to victory in his 200m semi-final, easing across the line in 20.18sec. Victory for the 25-year-old in Thursday’s final would better the record of American legend Carl Lewis, who won three golds and a silver in the sprints at the 1984 and 1988 Games. “People always doubt the champion but I know what I can do so I never doubt myself. This is my favourite event so I am looking forward to it,” said Bolt, who is targeting his own world record of 19.19sec. “It’s a possibility, definitely. I can’t say but the track is fast, it’s going to be a good race.” His main danger will come from compatriot and training partner Yohan Blake, who took silver in the 100m. Also on the track, world champion David Rudisha goes for gold in the men’s 800m while South Africa’s Caster Semenya, in her debut Olympics, runs in the women’s semi-finals. Oscar Pistorius, the first double amputee to take part in the Olympics, looked to have made a bitterly disappointing exit from the Games when South Africa crashed out in the first round of the 4x400m relay. But Pistorius was waiting on an appeal after teammate Ofentse Mogwane fell heavily before his changeover, a result of a collision with a Kenyan athlete.