Gawn passed a fitness test on a troublesome calf an hour before putting on a clinic in the Demons' 14.16 (100) to 9.8 (62) victory at the MCG on Sunday.
The imposing captain racked up 27 disposals, 10 clearances, seven marks and a goal as Melbourne (7-4) leapt from ninth position at the start of the day up to fourth on percentage.
But the win came at a cost, with versatile tall Harrison Petty substituted out with a foot injury.
Gawn gave his midfielders silver service and Alex Neal-Bullen (27 disposals), Clayton Oliver (24), Christian Petracca (24) and Christian Salem (32) cashed in.
Jacob van Rooyen (three), Bayley Fritsch, Jack Viney and Petracca (two each) all kicked multiple goals.
Adam Tomlinson stepped up as a replacement for injured defender Jake Lever and was outstanding alongside Steven May, the pair combining for 23 intercepts.
Tom McDonald also stood up in the Demons' brick wall of a defence, which restricted St Kilda to just five goals in the first three quarters.
Jack Steele (33 touches) and Jack Sinclair (30) fought hard in the midfield, but the Saints had few winners.
Key forward Max King (three) kicked multiple goals for just the second time in six weeks under close watch from May, and Jack Higgins booted two on return from suspension.
Melbourne dominated the opening quarter and Lachie Hunter marked his first game of the season with an early goal.
The inaccurate Demons didn't take full toll, leading 4.7 to 1.0 at the first break, but were in total control at that point.
With Gawn giving them first use, Melbourne's midfield generated a 22-8 advantage in forward entries and they claimed eight marks inside 50m before quarter-time.
St Kilda wrestled their way back into the contest in the second term, and two goals from King helped cut the deficit to 12 points at the main break.
But Gawn reasserted his authority at the start of the third term with a contested mark against direct opponent Rowan Marshall and a goal to kick-start his side.
It was the first of four in a row for Melbourne in a six-goals-to-one quarter that effectively ended the contest early.
Melbourne next take on finals hopefuls Fremantle in Alice Springs, while St Kilda face a long trip to take on West Coast in Perth.
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