The second race of the weekend was all but decided at the start when a clutch issue saw Aaron Cameron make a slow getaway from the outside of the front row.
That allowed polesitter – and Race 1 winner – Mawson to immediately skip from the chasing field, initially lead by Cooper Webster.
James Golding did eventually get past Webster for second but the Supercars regular had no answer for Mawson's pace, the two-time Gold Star champ streaking to victory.
A time penalty for Golding saw Webster promoted to second while Roberto Merhi rounded out the podium, the ex-Formula 1 driver spectacularly working his way through the field from ninth.
The Spaniard almost nabbed second after forcing Webster to defend into Turn 6 on the final lap, but Webster was just able to hold on.
That left Mawson on the verge of a rare clean sweep, only for a sluggish getaway at the start of Race 3 allowing Webster to jump into the early lead.
It was the first time Mawson had been headed all weekend, the Team BRM/88 Racing driver settling into a rhythm behind the leader.
As the race wore on Mawson started to pile on the pressure, before using his push-to-pass to perfection as he stormed down the inside of Webster into Turn 6 on Lap 15.
Webster tried to hang on to the new leader for a couple of laps, however a moment at Turn 2 gave Mawson the breathing space he needed to set up a third win of the weekend.
The clean sweep means Mawson will head to Phillip Island with a 29-point lead in the Australian Drivers' Championship over Webster.
"What a mega race," said Mawson. "It was tough out there following, but I used the strategy we came up with before the race, being very smart with the push-to-pass.
"I can't believe we had a clean sweep. What a mega weekend."
Golding rounded out the podium for the final race after tense battles with Garry Rogers Motorsport teammates Merhi and Cameron during the race.
The 2023 S5000 season continues at Phillip Island on May 12-14.
