Tyson Gay has rebounded from a leg injury which cost him a place on America's Olympic Games 200m team but acknowledged he will have his work cut out to challenge the "phenomenal" Usain Bolt and "dark horse" Asafa Powell over the 100m.
The reigning world double sprint champion, who will be 26 on Saturday, strained a hamstring muscle at the US trials in July to wreck his chances of repeating his world feat on the Olympic stage.
The American sprint king, who claimed double world gold in Osaka last year, then locked himself away at a training camp in the southern German city of Munich and is now raring to go.
"My state of mind is pretty relaxed," he said. "It (the injury) was a setback, especially mentally. But at the same time, I think it helped me being away from the media for a while; no interviews for three or four weeks.
"It's really kept me relaxed. I haven't had anxiety about the whole Olympics because I've just been in rehab, so I think it's really helped mentally."
Gay said his hamstring now felt "good".
"I've had a lot of treatment on it and this is the Olympics, so I'm sure that with all the adrenalin flowing I'm going to be at 100 percent. I'm going out there to win the gold medal even with all my setbacks."
Gay admitted that he would be the underdog in the 100m and acknowledged his disappointment at missing out on a berth in the 200m.
"I was really upset about missing out on the 200 metres. I mean I knew that America has up to five great athletes or more, so I knew someone wasn't going to make it. I just didn't think it was going to me.
"I was really upset about it, because my goal was to come back with three gold medals. Obviously, I'm going come up short this time, but I hope it will all go well next time."
Gay heaped high praise on Jamaican world 100m record holder Bolt, who is one of the firm favourites to achieve an Olympic sprint double not seen since Carl Lewis in the Los Angeles Games in 1984.
"Usain Bolt has done something no one's ever done and that's run the 100 metre dash that fast," he said.
"He's set the world on fire with the 9.72, the 9.76 and the 9.8sec. He's on fire right now. And a 19.6 just to top it all off (in the 200), it shows that he's an all around athlete.
"That's what I respect about him. What he's done so far has been phenomenal."
But Gay did not rule out Bolt's compatriot Powell, the previous world record holder coming back into form, and predicted that the 100m would be one of the Olympics' most exciting races.
"Asafa should be the favourite with the most 9.7sec. But he's been the dark horse and I think that's how he likes it. He doesn't have any pressure on him.
"The whole of his country is looking to Usain to bring home the gold medal and it only makes sense. But he's still a tough competitor and I know he's going to great things.
"I've been racing Bolt since 2005 in the 200m. They've been some of my best races against him down in Jamaica, and Asafa Powell's been the 100m king.
"Those two guys give it their all anytime they're racing whether it be 100 or 200m."