The 88Racing Team BRM driver led from lights out to flag fall, and managed the push-to-pass with time in hand for a 1.7s victory.
“I used it early, and then after the Safety Car to hold off Webster, who I imagine was using it to try and pass me,” Mawson said.
“But I had 10 seconds' worth after I got clear and then used that to get the fastest lap.”
Versa Motorsport's Cooper Webster, who was on the pole, was second throughout and was disappointed with his start.
“I didn't get the best start, just lost it in the second phase of the launch,” he said.
It was only in the latter stages that Golding was able to get by Cameron, which he did out of Turn 4 on the penultimate lap.
“The push-to-pass is something you really have to think about,” Golding said.
Blake Purdie finished in fifth place ahead of Nic Carroll and Winston Smith.
It was not a good outing for Mark Rosser. He was turned around at MG on the first lap and then went off at Turn 4 on Lap 4 with a deflated tyre from a broken valve stem. That brought out the Safety Car for two laps before racing resumed.
Jordan Boys was another who did not finish. He spent most of his race chasing Purdie in sixth place before he parked the GRM car at Siberia with a broken gearbox.
Action continues tomorrow as part of the Shannons SpeedSeries, streamed live and ad-free on Stan Sport in Australia, and free on Speedcafe for international viewers.