The 19-year-old, the third youngest rider in the field, is based in the USA this year with the Bontrager Livestrong team.
Fellow Kiwi Jason Christie, based in Belgium this year with a professional team, was 45th in 48:45.78.
The elite action is under way tomorrow when Linda Villumsen competes in the elite women's individual pursuit.
The Orica-AIS professional is aiming for her fourth straight medal in this discipline after bronze medals in Mendrisio 2010 and Melbourne 2011 and a silver medal in Copenhagen last year.
The elite men's time trial is on Thursday, with London Olympic medallists Jesse Sergent and Sam Bewley riding for New Zealand.
Results: Under-23, 36km: Anton Vorobyev (RUS) 44:09.02, 1; Rohan Dennis (AUS) 44:53.41, 2; Damien Howson (AUS) 45.00.14, 3. Also New Zealanders: James Oram (North Harbour) 47:52.97, 37; Jason Christie (Ashburton) 48:45.75, 45.
Junior men, 26.6km: Oskar Svendsen (NOR) 35:34.75, 1; Matej Mohoric (SLO) 35:41.79, 2; Maximillian Schachmann (GER) 35:46.58, 3. Also New Zealanders: Hayden McCormick (Te Awamutu) 36:45.52, 23; Nick Bain (Auckland) 37:44.37, 39.