Newtownards cyclist Martyn Irvine is ninth after the first discipline of the omnium event in London.
Irvine was competing in the flying lap, the first of the six disciplines, with the points race and elimination race also taking place on Saturday.
The individual pursuit, scratch race and time trial are held on Sunday.
Great Britain’s Ed Clancy tops the standings at the London Velodrome followed by Shane Archbold of New Zealand and Australia’s Glenn O’Shea.
Irvine faced a huge task to qualify for the Olympics but achieved his goal by breaking into the top eight in the European rankings.
“I’ve been training with a medal in mind – It’s all about putting together my best races on the day,” he said before the Games.
“And If I can accumulate my best six races, I’m well able to be standing on the podium in London.”