Liam Phillips was handed a tough draw in the BMX quarter finals after progressing 10th fastest from the seeding race.
The 27-year old from Manchester, who won World Championship gold in 2013, finished his time trial in 35.905 as 2016 world champion Joris Daudet of France led the way on 34.617.
Phillips’ time puts him in heat two of the eight-man quarter finals, alongside defending champion Maris Strombergs as well as world medallists David Graf, Tory Nyhaug and Luis Brethauer.
The Brit will need to finish in the top four of his quarter final after three races tomorrow to progress to the semi final stage.
And Phillips, who reached the final at London 2012, insisted he had plenty left in the tank for once the racing starts in earnest.
“We haven’t put too much emphasis on going out and getting a really good qualifier in,” said Phillips, who broke his collarbone just eight weeks ago.
“It was more about getting out, soaking up the atmosphere, having some fun and trying to get ready for tomorrow. That’s when it counts.
“The track is really, really fast and the minute you make one small mistake, that just knocks on to the rest of the lap.
“Down the second straight I made a small mistake and lost a little bit of speed and that’s all it takes.
“We all know getting to the first corner first is crucial for success in a BMX race and I know that part of my race is pretty good.”
Teammate Kyle Evans was 21st from the seeding run, coming through in 35.776.
And the Brit admitted his first racing lap of the track had helped settled any nerves on his Olympic debut.
““Overall the lap was okay and it’s just nice to get away and get the nerves settled and hopefully be on our way for a good weekend,” said Evans.
“Once I got on for practice, most of my nerves went away and I felt ready to go and I’m happy with that.
“Now the pressure seems to have come down a little bit and it just feels good to get out there with the first day, get that out of the way and now we can look forward to the next couple of days.”