In defeating Central Coast Mariners 3-1, Muscat's side finished with 53 points, three clear of second-placed Sydney FC which won 2-1 over Wellington earlier on Sunday.
Muscat, who captained the club to the 2008-2009 premiership and championship double, said he was "over the moon" after steering Victory to the Premiers' Plate in his first full season as manager.
As a veteran of English football, which does not have finals series, Muscat suggested there was a temptation to relish this occasion more than a grand final win.
But Muscat said his eyes are set on finals glory.
"If you ask any traditionalist, they'd put these nights... down as the biggest nights," he said.
"Australian sport loves grand finals and so do I.
"It was a very good night for us, a massive night for the football club."
Victory now has a week off from finals, with Muscat saying the players would celebrate with gusto.
"You've got to enjoy the good times and tonight is certainly a good time," he said.
"We've won the most games, scored the most goals, conceded the least goals.
"It's a massive achievement and the playing group should be really proud of themselves."
Daniel Georgievski, Archie Thompson and Besart Berisha scored Victory's goals, with Eddy Bosnar netting in reply.
Sydney also has a week off, pushing Wellington to fourth with its win in New Zealand.
Winners from week one will play Victory and Sydney FC in week two for a place in the A-League grand final.
Mariners coach Tony Walmsley said while Victory's strong attacking finish to the league season makes it justified favourite to win the grand final, the others are still a good chance.
"It's finals football, it could go anywhere," he said.
"I'd say Melbourne Victory but I'm not a punter so very hard to say."
