Besart Berisha grabbed his fourth goal in three A-League finals in the first half but it was not until Kosta Barbarouses and Leigh Broxham goals in the last seven minutes that the scoreline reflected the dominance of the Dark Blues.
Victory are only the second team to win a hat-trick of Australian titles in the 10 years of the league after the Brisbane Roar, for whom Albanian Besart scored twice in the 2012 final and once in last year's championship decider.
"Better is not possible, we played an incredible season, we are the best attacking team and the best defending team," the fiery striker told the crowd of 29,843 fans at Melbourne's Rectangular Stadium.
"If this is not the best club in Australia then people should, I don't know, shut up. This is unbelievable."
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Sydney, who had also been chasing a third title, were a shadow of the team that set the pace in the second half of the season and crashed to their first away defeat of the campaign.
Victory monopolised territory and possession in a tempestuous opening to the match and they got their reward in the 34th minute when Berisha controlled a ricochet off Gui Finkler and lashed the ball into the corner of the net with his left foot.
Sydney FC had a chance to equalise just before the break when a neat one-two between Marc Janko and Alex Brosque gave the Sky Blues' skipper space for a shot from the edge of the area but Victory keeper Lawrence Thomas saved well.
Melbourne came out firing after halftime and Barbarouses should have scored Melbourne's second but blasted his shot into the legs of Sydney goalkeeper Ivan Necevski.
Clear chances were at a premium but Austrian Janko could have levelled the scores with a header from the penalty spot in the 76th minute only to guide it straight at Thomas.
Seven minutes later Barbarouses burst forward into the area, exchanged passes with Fahid Ben Khalfallah then kept his nerve when his first attempt on goal was blocked and buried the ball in the back of the net.
There was still time for Victory defender Carl Valeri to be sent off for a second yellow card before Broxham smashed the third goal into the net to put a gloss on the win.
Australia's octogenarian football supremo Frank Lowy fell off the stage during the post-match presentation but recovered sufficiently to present skipper Mark Milligan with the trophy.
(Reporting by Nick Mulvenney, editing by Amlan Chakraborty)
