The reigning Australian Drivers' Champion made a perfect start from pole position, comfortably out-dragging Cameron to the first corner.
James Golding got by Cameron on the run to Turn 1 as well as Mawson settled into the lead ahead of the Garry Rogers Motorsport pair.
Golding's charge only last several laps, a broken steering arm forcing him into the pits on just the second lap.
Cameron was happy to take up the fight, though, closing up on Mawson as the race reached its mid-point.
But while he was able to stick to Mawson's rear wing there was no way past, Mawson holding on to win by four-tenths.
The battle for the final step of the podium was equally tense, Tim Macrow edging Nathan Herne by just three-tenths of a second.
Shae Davies finished a distant fifth ahead of Cooper Webster and Blake Purdie.
Golding, meanwhile, got going again but was five laps down and ultimately classed as a DNF.
There will be two more S5000 races tomorrow at 12:05pm and 2:15pm local time.
