Perry spearheaded the Sixers to the third-highest successful run chase in WBBL history with a blistering 81 from 38 balls at Adelaide Oval on Sunday night.
The Sixers were cruising in pursuit of the Renegades' 8-178 but fell into a hole by losing 5-26 after Perry was dismissed.
But Bray, who only turned 15 last month and is in Year Nine at school, combined with Sarah Bryce (36*) to help the Sixers home with six balls to spare.
Bray smashed the ball over cover for four to secure the victory for the Sixers in their first game of the tournament.
Ellyse Perry of the Sydney Sixers hits out on her way to 81 off 38 balls against the Renegades. (Matt Turner/AAP PHOTOS)
"It's pretty cool," Bray told the Seven Network.
"I wasn't expecting for it to go that well.
"It literally is a dream come true.
"She (Perry) gave me my cap before the game and I was crying a little bit, maybe more than a little bit."
Perry, who is 19 years older than Bray, was blown away by what the youngster did on debut.
"For a 15-year-old to hit a ball over extra cover to win the game is amazing," Perry told the Seven Network.
"She bowled really well too. She's a really special kid."
Charli Knott's 44no lifted Brisbane to victory over Adelaide. (Matt Turner/AAP PHOTOS)
Earlier, Brisbane turned the tables on Adelaide, winning a rematch of last year's WBBL final by four wickets.
In the first game of the 10th edition of the WBBL, the Heat suffered some nervous moments in the chase at the Adelaide Oval before reaching the Strikers' 5-133 with 12 balls to spare.
Charli Knott (44 not out) proved a steady hand for Brisbane when they lost 3-9 as they closed in on the target.
Australian star Megan Schutt claimed two quick wickets to give Adelaide a sniff of a miracle victory.
But Knott, 21, closed out the win with a lofted drive for two runs to be named player of the match.
Adelaide, gunning for a third-straight title, never got going with the bat on their home ground despite an unbeaten 51 from captain Tahlia McGrath.
In her first game for the Heat, Indian quick Shikha Pandey took 2-14 from her four overs, including the key wicket of Strikers opener Laura Wolvaardt.
To finish off the day, Perth will host the Melbourne Stars at the WACA Ground.
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