Mawson made a slick start from the outside of the front row, sweeping into the lead ahead of polesitter James Golding through the turn 1/2 complex.
Golding, meanwhile, immediately dropped back in the field, ending up fourth behind Cooper Webster and Aaron Cameron.
Once back in his rhythm, Golding stalked Garry Rogers Motorsport teammate Cameron for a lap before diving down the inside to claim third place at turn 3.
He then closed up on the back of Webster, using push-to-pass to executive another move at turn 3 to grab second place on lap 7.
By that point he was 3.5 seconds behind Mawson with 10 laps left to run.
However Golding was able to quickly run down that gap, a series of fastest laps getting him within a second of the lead by lap 10.
On lap 12 Golding copped what looked to be a break when Mark Rosser hit the wall at turn 4 to bring out the safety car.
That put him right behind Mawson for a single-lap dash to the chequered flag.
Mawson did actually make a small mistake on the restart, locking a brake on the way into turns 1/2. However he was able to keep the car on the road, unlike Golding and Cameron who both went skidding off the road.
That left Mawson clear to streak to a one-second victory, with Webster reclaiming second and Blake Purdie popping up in third.
Jordan Boys came through the late drama to end up fourth while Cameron managed to get back on track and finish fifth.
Golding finished seventh behind Winston Smith.
The weekend continues with two more races tomorrow.
