Usain Bolt (C) of Jamaica crosses the finish line ahead of Jimmy Vicaut (L) of France and Kamil Krynski of Poland during the men's 4x100 metre relay final at the IAAF World Championships in Daegu in this Sept 4, 2011 file photo. [Photo/Agencies]

Usain Bolt insisted "this is my time" ahead of his bid to become the first man to win back-to-back Olympic titles, despite the emergence of Jamaican rival Yohan Blake.

Bolt told Britain's Guardian newspaper that he was ready to cast off an indifferent build-up and make history at London 2012, four years after his show-stopping performance at the Beijing Games. "This will be the moment, and this will be the year, when I set myself apart from other athletes in the world," he said.

"A lot of legends, a lot of people, have come before me. But this is my time... I've been saying this for years. This will be the year. This is my time."

The 1.96-meter Jamaican lit up Beijing's Bird's Nest stadium in 2008 when he smashed the 100m world record to claim gold with apparent ease, raising his arms in celebration well before crossing the finish line. Bolt, now 25, also galloped to victory in the 200m in another world record time, and helped Jamaica win the 4x100m.

But the world's fastest man has had an unexpected rocky preparation for the London Games. Bolt ran his slowest 100m in three years at Ostrava in May, and last month he was stunningly twice beaten by the 22-year-old Blake in both short sprints at the Jamaican Olympic trials. He later withdrew from the Monaco Diamond League meeting citing a "slight problem", sparking intense injury speculation, and was also involved in a minor car crash.

But Bolt said losing to Blake had helped him recapture his focus.

"It's always good to lose. It wakes you up," he explained. "Each training session I'm getting better and better," Bolt added. "I have no other duties now, no worries, it's all about training, eating and sleeping.

"I have a lot more time and can put a lot more effort into training. I'm feeling better every day. As long as I'm feeling myself I'm definitely in no doubt I can go to the Olympics and win."

Bolt also said the Olympics would prove a big test for Blake, who is amongst a high-quality field also including Tyson Gay - "one of the fiercest athletes out there" - Asafa Powell and Justin Gatlin.

"It's a packed race with top-class athletes so it will be a different level of competition for Yohan. It's going to take a lot of focus. And it's going to cause a lot of stress," said Bolt.