Paris: Usain Bolt set two new world records and harvested three gold medals in his last outing at the world championships, but the Jamaican has insisted that a further improvement in times for the 100 and 200m at Daegu is unlikely.

After storming to the sprint double in then-world record times at the Beijing Games in 2008, Bolt bettered that performance with a 9.58 and 19.19sec in the two events in Berlin a year later.

But an injury lay-off has put paid to any thoughts he harboured of going even faster in the August 27-September 4 worlds in South Korea, the 24-year-old at pains to remind fans he is "only human" and that constant expectations of quicker times are unrealistic.

"I'm not worried about either the 100m or the 200m, my best event," said Bolt, after coming within centimetres of suffering only the third defeat of his professional career in the Monaco Diamond League meet.

"It's always key to keep winning. I'm never going to get to 9.58sec this season, I'm not at the same level as two years ago. I'll try to get a 9.7sec or maybe 9.6."

The Jamaican made it clear that the Daegu worlds were one small step on the way to the 2012 Olympic Games in London, where, like the worlds, he will attempt to repeat his triple gold medal showing from the Beijing Games.

"I'm working my way up to the Olympic season, to being fit and ready then. London is the key," Bolt said.

"There are some little things to work on. I have time before the world championships and I will continue to do my best."

So big is the public's expectation from Bolt, it is sometimes easy to miss the fact that he has so far gone undefeated this season in both the 100 and 200m.

Disappointment at "slow" times aside, Bolt remains the world's top sprinter although compatriot and former world record holder Asafa Powell has the season's lead over the shorter distance.

Commanding astronomical appearance fees of some 300,000 euros, the Jamaican has become the main drawcard for every meet he attends and is undoubtedly the biggest name in world athletics - something that grates for some athletes.

Australian discus thrower Benn Harradine said the Bolt phenomenon was "killing it for everyone else", arguing that throwing events in particular were given short shrift by meet organisers.

"In Oslo the meet appeared to have absolutely no interest in the marketing of other events whatsoever," the Commonwealth champion argued on his blog.

"The entire telecast kept referring to their 'countdown to Bolt' while other athletes, who are also world champions, Olympic champions just filled the time in until he ran for 20 seconds or less.

"Don't get me wrong, I think Bolt is doing a lot of good for our sport too, and is a major drawcard for ticket sales, but package the meets into athletes of world class quality across diverse fields and give them the chance to shine.

"What is going to happen if Bolt ruptures his Achilles, or tears a hamstring and is out for the season?"

(Agencies)