Liam Phillips described his first competitive ride at the London 2012 Olympic Velopark as "mind-blowing" after qualifying 12th for Thursday's BMX quarter-finals.
The 23-year-old from Burnham-on-Sea bounced back from a broken collarbone sustained at May's BMX World Championships in Birmingham, a day after winning time-trial silver, to qualify in 38.719 seconds as Raymon van der Biezen of Holland advanced in first place in 37.779secs.
Three-time world champion Shanaze Reade, meanwhile, qualified fifth in the women's event, which resumes with Friday's semi-finals.
Phillips worked as a commentator at last August's test event while trying out for the track team as a specialist starter in the team sprint before returning to BMX the following month.
He said: "This is what I wanted. I like riding on the track, but it didn't float my boat.
"This is where I belong. Whatever happens in terms of results, I'm here to enjoy it and to have 6,000 people that have paid to come and watch a sport that I've done since I was five years old is mind-blowing."
Phillips was drawn in the second quarter-final heat, with five runs to determine whether he will advance to Friday's semi-finals. The Somerset rider was satisfied with his ride and believes his form is good despite the shoulder problem.
"It's not great, but I've never really had any exposure to 6,000 people screaming your name," said Phillips of the qualifying ride. "It's a good start, but I'm looking forward to tomorrow."
Reade was fifth in the corresponding women's event, clocking 39.368 as world time-trial champion Caroline Buchanan of Australia advanced as fastest qualifier in 38.433.
"It felt quite good out there. The first race is always going to be a bit rusty," said Reade, who won the test event last summer. "It was amazing to compete in front of a home crowd."