Jamaican sprint superstar Usain Bolt on Thursday played down soaring expectations at the world championships in his "comeback season", insisting he still has work to do to become a legend. The defending Olympic and world champion in the 100m and 200m, speaking two days before he launches his bid for glory in South Korea, said breaking his own world records was unlikely as he makes his way back from injury. "This for me is a comeback season from injury. I have been working really hard this season to get back in tip-top shape," said Bolt, who dominates the sport of athletics, commanding huge appearance fees. The 25-year-old said the Daegu worlds were crucial as he aims for the extra success he believes he needs to go down in the record books as one of the legends of athletics, even though for most he long ago achieved that status. "I've said throughout the season that the world championships is pretty much going to be the first step towards becoming a legend so it's very important," Bolt said at a Jamaican team press event. "You have to take the first step before you take the second, which would be the Olympics (London 2012) so I'm really focused on going out there and doing my best. I'm just going out there to win and that's the main focus right now." After storming to the sprint double in then-world record times at the Beijing Games in 2008, Bolt took his sport to new heights in Berlin a year later with a 9.58 and 19.19sec. He also won the 4x100m relay at both events. But an injury lay-off has stymied a bid to go even faster at the worlds in South Korea, which start on Saturday, when Bolt will run in the 100m heats. The sprinter said the challenge had been getting back into shape and honing his technique, adding: "I wouldn't say it's 100 percent but I'm happy with where it is and I'm going out there to do my best." Speaking about the weight of expectation, Bolt said: "I think people expect a lot from me. I'm personally focused on winning always but for me the pressure is always there, even before I won my first gold medal." The defending champion said he would be forced to take everybody seriously given he was not at his best, even though main competitors Asafa Powell and American Tyson Gay are missing from the worlds. Bolt remains the world's top sprinter, though compatriot and former world record holder Powell has the season's lead over the 100m, with Gay second quickest.