Under-fire Carlton forward Harry McKay kicked three majors in a low-scoring affair but the Demons had a greater spread of contributors in their 8.13 (61) to 6.8 (44) victory at the MCG.
It came at a cost when Jake Bowey was substituted out during the third term on Friday night after an accidental knee to the head from teammate Jake Lever in a marking contest.
The Blues lost tall utility Jack Silvagni to a hip injury before halftime on their way to a seventh defeat in eight matches, pouring further heat on Michael Voss' side after another turbulent week.
Petracca shone in the absence of injured midfield partner Clayton Oliver, tallying 32 disposals, 18 contested possessions, eight clearances and a goal.
Jack Viney (20 disposals, seven clearances, six tackles) was also tough in the clinches as the Demons dominated clearances (38-29) and contested possession (148-122).
Ed Langdon (25 disposals), Trent Rivers (24) and Angus Brayshaw (24) won plenty of the ball and Bayley Fritsch (two) was Melbourne's only multiple goal-kicker, while All-Australian defender Steven May blanketed Charlie Curnow (one goal) for most of the night.
"It wasn't pretty and there were some inefficiencies but from our perspective it was a fairly dominant performance," Demons coach Simon Goodwin said.
"We had 40 front-half turnovers and defended incredibly well all night.
"I was really proud of our boys. They didn't waver one bit in their mindset and mentality, and you could feel that all night.
"They bought into the right things and we've still got work to do, and I'm sure that will be the talking point, but internally we're really rapt with the performance."
McKay has endured an intense spotlight on his goal-kicking in recent weeks and breathed a huge sigh of relief when he slotted Carlton's first goal from a mark and snap in the pocket.
He started with two straight majors but got a little wayward later in the match, finishing with 3.2, while another shot fell short when he chose to snap from 40 metres.
Adam Cerra (30 disposals, four clearances), Sam Docherty (26, four) and Patrick Cripps (23, five) tried to turn the tide for the Blues as Tom De Koning fought hard in a ruck battle with Max Gawn and Brodie Grundy.
Carlton twice got within 11 points during the final term before a long bomb from Gawn, who stood tall late in the match, gave Melbourne breathing space in an error-riddled slugfest.
The Demons kept their opponents to just 39 forward entries as both sides posted their lowest score of the season.
"We're fighting but we're forcing and it's making it look really hard," Blues coach Voss said.
"The endeavour to try and do the right thing has been a bit that way for most of the year.
"The boys keep fighting but right now there's a phase of the game where it's proving pretty hard to get ticking over."
The result put Melbourne (8-4) back on the right path after consecutive losses and extended Carlton's horror run, in which their only win over the last eight rounds came against lowly West Coast.
The Blues (4-1-7) have posted five straight losses for the first time since the six-match streak in 2019 that brought down the axe on Brendon Bolton's time as coach.
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