Jess Duffin hit a single off the last ball of Marizanne Kapp's super over to snatch the win for the Victorians; their nine runs in the extension eclipsing the Sixers' 2-8.
It was the second celebration of the day for the Renegades who fleetingly thought they'd defended their 7-120 in regulation play.
Sixer Sarah Aley, needing three to win off the last ball of the final over, inside-edged Amy Satterthwaite to short fine leg for what appeared to be just a single.
Kris Britt threw the ball to Renegades keeper Emma Inglis who instinctively and prematurely started celebrating - but didn't break the wickets.
Aley, showing tremendous match awareness, scampered back for a second run to tie the scores, her quick thinking beating the desperate efforts of Sattherthwaite who cottoned on to what was happening but couldn't execute the run out.
The Sixers had been in control at 2-81 in the 13th over when Maitlan Brown's diving outfield catch to dismiss WBBL leading run scorer Ellyse Perry (37), off the bowling of Chamari Atapattu, turned the match on its head.
Atapattu (2-6) then got rid of the dangerous Erin Burns (20) in her next over, exposing the Sixers' lower order who could only scramble a tie.
Earlier player-of-the-match Satterthwaite's measured 44 combined with Inglis's turbo-charged 31 off 17 balls had rescued the Renegades from a dire position of 3-17 after seven overs.
South African legspinner Dane van Niekerk (2-25) dismissed the dangerous duo in her last over to extend her advantage atop the WBBL wicker-taking leaderboard but Satterthwaite and the Renegades, secured victory in the end.