The A-League Men (ALM) club was shoved into the spotlight for all the wrong reasons in May when now-former players Ulises Davila, Clayton Lewis and Kearyn Baccus were arrested over an alleged bet-fixing ring.
But the Bulls put that drama behind them, at least temporarily, with their triumph, coach Mile Sterjovski's first silverware, in front of a hostile crowd of 13,289 fans at AAMI Park on Sunday night.
Bulls recruit Marin Jakolis scored the winner against the run of play in the 58th minute, while goalkeeper Filip Kurto starred as Victory coach Patrick Kisnorbo's decision to leave Daniel Arzani out of his squad altogether backfired.
Victory had a penalty shout, for a foul on Kasey Bos, waved away in the 18th minute but were left to rue their failure to take their chances, failing to score despite dominating shots 22-6.
The Jakolis winner was Macarthur's only shot on target, compared with Victory's six.
Victory's official line was that Socceroos winger Arzani was left out because he is suspended for their round-one ALM grand final rematch against Central Coast, and Kisnorbo had wanted to test players available for that game.
But with a trophy and 2025 Asian Champions League 2 spot - now Macarthur's - on the line, the decision raised eyebrows.
A Victory spokesperson denied there had been any falling-out between Arzani and Kisnorbo, when approached by AAP.
But the winger's creativity and guile were sorely missed as Macarthur scored on the counter, then sat deep for the final 35 minutes.
Melbourne Victory's Daniel Arzani (right) watched the Australia Cup final from the stands. (Morgan Hancock/AAP PHOTOS)
Victory were incensed when Bos didn't receive a penalty after he was cut down by Kealey Adamson.
But referee Jonathan Barreiro waved his pleas away, and there is no VAR in the Australia Cup.
Four minutes later, Zinedine Machach brilliantly slipped through Reno Piscopo, but his first-time shot was comfortably saved by Kurto.
In the 25th minute, Kurto denied Nishan Velupillay, before Nikos Vergos blasted over the bar.
Kurto pulled off an extraordinary diving save to bat away a skidding Velupillay shot in the 40th minute.
Victory skipper Roderick Miranda turned a header wide in the 53rd minute.
After Victory had spurned so many chances, Macarthur only needed one to make them pay.
Released by Walter Scott, Jed Drew burst away on the counter and, under pressure, had the presence of mind to square the ball for Jakolis to sidefoot home.
Victory had late chances but couldn't equalise.
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