ROME (AFP) - World record holder Usain Bolt says he wants to prove to the world he's still the best in the business when he makes his comeback to the track here on Thursday after nine months out. The Jamaican has not raced since August when he was beaten by American Tyson Gay. The American won't be at the Golden Gala meeting at Rome's Stadio Olimpico but Bolt's old domestic rival Asafa Powell, the former world record holder, will be there to provide stiff opposition. Bolt has made a few changes since he last raced, bulking up on muscle and working on his start. He says he hasn't lost any confidence in himself despite that defeat to Gay in Stockholm and now wants to remind everyone who is the boss. "You lose some, you win some, you never win every race in your entire career," he said. "Last season wasn't my best, it was down time for me. This season it's back to business. I'm really focused, I'm ready now and I'm out to prove to the world I'm still the best." And although Bolt isn't used to losing he says no-one should be surprised that he was beaten by Gay. "Tyson Gay is definitely one of those sprinters that never gives up, he's really determined," said the 24-year-old. "He doesn't drink, he doesn't party, he's really focused on what he wants, he's a complete athlete and a wonderful competitor." Gay isn't running in Rome but Powell is and Bolt doesn't want to suffer a second defeat to his compatriot. Powell has beaten him just once in nine outings, and that too was in Stockholm back in 2008. But while Bolt is the world record holder over 100m and 200m and Olympic and world champion in both.