The Victory will return home to Melbourne next weekend with a two-goal advantage after Bunge struck twice in the second half at Coopers Stadium on Sunday.
Adelaide will have to beat Victory in Melbourne for the first time in nine years to reach the decider, which will be against the winner of Melbourne City and Central Coast.
Victory star Emily Gielnik struck in the 38th minute before Adelaide's American attacker Erin Healy hit back.
But Bunge headed home from corners in the 77th and 88th minutes to deliver Victory a terrific away win in front of 4372 fans at Coopers Stadium.
Gielnik pulled up sore and came off in the 67th minute while Adelaide defender Tiarna Karambasis was replaced by Chelsie Dawber after a head knock in the 62nd minute.
The game burst into life when Victory goalkeeper Courtney Newbon found Gielnik with a wonderful defence-splitting pass.
Gielnik let rip with a wonderful left foot strike that clattered home.
But Adelaide responded almost immediately.
Fiona Worts won the ball in midfield and worked it out wide to Emily Hodgson, whose cross fell to Lucia Leon.
Emily Condon forced a good save from Newbon but Victory's defence were unable to clear it quickly enough and an unmarked Healy nipped in to score.
Victory were controversially given a free kick for handball in the 43rd minute when the ball had appeared to hit Healy in the head, not hand.
But Reds goalkeeper Claudia Jenkins pulled out a world-class save to turn a ripping free kick from Alana Jancevski over the bar.
Both teams traded chances but Victory's winner came after Jenkins made another impressive save to deny Sara D'Appolonia in the 76th minute.
At the subsequent corner, Alana Murphy whipped in a flat delivery to the back post and Bunge managed to push off Dylan Holmes to make space before powering home a bullet header.
Eleven minutes later, Bunge again got the better of Holmes to nod home an Alex Chidiac cross.
Dawber forced a good save from Newbon in the 93rd minute but Adelaide couldn't hit back again.
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