After he finished second twice to his TekworkX Motorsport team-mate Nash Morris, the victory gives Shields the round win after his Morris came home twelfth.
It was Shields second race win of the season and it also meant he took out the round overall at Sydney Motorsport Park. While he led from the outside of the front row, Morris bogged down from his pole position and slipped to third behind Earl Bamber Motorsports' Marco Giltrap.
Behind them in the background there was contact between Matt Slavin and Andrew Goldie into Turn 1 where both speared off. Slavin continued but Goldie was stranded as too Class B's Brad Carr who had a drama and the start and only made to the inside of the first corner.
The Safety Car ensued for the following three laps before racing resumed. Shields continued to lead while Morris snared second off Giltrap at Turn 6. Morris then put the pressure on Shields but came unstuck at Turn 10 midway through with a spin at Turn 10 and resumed 15th.
Giltrap had lost his third spot to Grove Racing's Oscar Targett who staved off the challenged from TekworkX's Hamish Fitzsimmons in the later stages. Ninth at the end of the first lap, Sonic Racing's Ronan Murphy made up places and finished fourth ahead of Giltrap, and EBM's Zak Stichbury.
McElrea Racing's Lachlan Bloxsom was fourth in the early running but slumped down the order to ultimately cross the finish line seventh ahead of Marcos flack, Tom Taplin and Pro-Am winner Adrian Flack.
Harrison Goodman was next and ahead of the recovering Morris, Tom McLennan, Caleb Sumich and Sam Shahin who was second in Pro-Am. Third in the class and 16th was Casper Tresidder from Richard Cowen and Slavin while Class B went to Lachlan Harburg.
Despite the Race 3 result, Morris was second for the round in Pro ahead of Giltrap, Bloxsom and Targett. Adrian Flack was unbeaten over the weekend in Pro-Am and won ahead of Slavin and Shahin while consistency worked for Stephen Moylan to take Class B in front of Brayden Taylor and Phil Morriss.