Representing Peel District Cycling Club, Thurlby attacked halfway up the challenging final 2.8km River Road climb, which has an average 10 per cent gradient, but was caught just 50 metres from the finish line.
Regular visitors to Peel races Luke Howe and Lachlan Connan took first and second place respectively, with Thurlby settling for third.
Rockingham’s Liam Magowan attacked at the base of the same climb in the B-grade race, but was caught and passed by his counterparts in the breakaway group to finish fifth.
The A-grade race saw regular Peel race visitor Tim Sellar successfully attack and break away on the first lap, however by the second Guy Kalma had ridden in pursuit of the lone leader.
Get in front of tomorrow's news for FREE
Journalism for the curious Australian across politics, business, culture and opinion.
READ NOWA mechanical problem allowed Kalma to catch the tiring Sellar, before three riders attacked from the reduced bunch at the base of the final climb up River Road, but Kalma managed to outsprint Sellar to take the State title.
Peel’s Luke Pledger finished sixth overall, but was the best-placed Masters (over-35) rider.
Mandurah’s Cass Higgs rode away from the bunch with Jessica Allen and held on to win the women’s title.