In one of the greatest nights in Australian domestic soccer history, former NSL powerhouses South first took Victory to extra time then fought back from 1-0 down to level it at 1-1 at the death before winning 4-3 on penalties in front of a pumping sellout crowd of 29,911 fans at AAMI Park.
South Melbourne, who have long craved an A-League licence, only strengthened their bid for that with a win that capped off an extraordinary evening.
Denis Genreau scored an athletic, improvised half-volley in the 95th minute to put Victory in front, before Max Mikkola forced home an equaliser in the 117th minute to send the game to penalties and the crowd into ecstasy.
In the penalty shootout, South goalkeeper Javier Lopez was the hero and won the Mark Viduka Medal as man of the match.
Lopez initially saved former South captain Harrison Sawyer's penalty but was ruled to have come off his line - but then saved the re-take too.
South scored all their penalties before Victory skipper Jason Davidson, son of South great Alan Davidson, hit his must-score spot-kick over the bar.
In becoming the first NPL team to win the Australia Cup, Sinisa Cohadzic's South succeed where Heidelberg last year and Sydney United 58 in 2022 could not.
With the win, South also technically claim a berth in next season's Asian Champions League 2 competition.
The defeat also extends Victory's silverware drought, with the club's most recent trophy the 2021 Australia Cup.
South certainly played up to the occasion, taking the game to Giovanni Savarese's Victory and making their mark on their biggest night in years in an incredible atmosphere.
A huge contingent of their fans packed the south end of AAMI Park, holding banners of club legends including Ange Postecoglou, Ferenc Puskas and John Margaritis.
The only lowlight of the night was a section of the crowd at the South end booing the Welcome to Country before the match.
On the field, South Melbourne attacking pair Juach and Yuki Uchida gave the Victory defence headaches all night.
Lopez made several great saves while Victory counterpart Jack Duncan was called into action on multiple occasions in regular time.Â
Victory should have taken the lead in the 78th minute when Guillermo May squared the ball to Santos but the Brazilian's poor shot allowed Lopez to make an extraordinary save with his knees
But there was nothing Lopez could do in extra-time to stop himself being lobbed by Genreau's strange half-volley, which bounced over the line before he could grab it.
Juach spurned a couple of great chances to equalise and the game appeared lost for South.
Then, with the clock winding down, South substitute Jordan Swibel burst down the right and sent in a ball that caused chaos and ended with Mikkola toe-poking home.
AAMI Park erupted and when the game was sent to penalties minutes later, only one club ever felt on top.
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