Commonwealth Games champion Sam Webster had to dig deep to claim victory in the sprint final on the first day of the BikeNZ Classic in Cambridge.
The UCI event is the first to offer qualifying points towards the Rio Olympics and has attracted riders from Australia, USA, Malaysia, Scotland, Canada and the Czech Republic.
Webster, who won the sprint and team sprint gold medal in Glasgow, had to overcome an impressive performance from 20-year-old Australian prospect Jacob Schmid in the three-race final.
Steph McKenzie was beaten in the women's sprint final by Australian Caitlin Ward.
The men's omnium competition is delicately placed after three of the six disciplines with 2011 world champion Aaron Gate from Auckland sandwiched between Australians Sam Welsford and Scott Law with only four points separating the trio.
The women's omnium was dominated by brilliant Australian Ashlee Ankudinoff who won all three disciplines - the scratch race where she dominated, the 3000m individual pursuit in 3:39.095 and the elimination. She leads from compatriot Rebecca Wiasak and Kiwi Lauren Ellis.
In Friday's racing the sprinters compete in the keirin with the omnium riders to complete their competition, along with a points and scratch race for endurance riders in the evening.