Sydney Sixers 177 for 4 (Gardner 36, Burns 35, Voll 2-29) beat Brisbane Heat 176 for 7 (Kerr 65, du Preez 42, Perry 3-40) by six wickets

Chasing 177 at the Allan Border Field, Sixers started the chase strongly but still needed 38 runs off the last four overs. The match turned when Carmichael and Brown hit 22 runs off the power surge. Needing seven runs off the last over, Carmichael and Brown nudged left-arm spinner Jess Jonassen for ones and twos as Sixers clinched a tense victory with one ball to spare.

Sixers, last season's finalists, are now just two points behind fourth-placed Heat, who could have sealed a spot in the finals with a victory.

With their slim finals hopes on the line, Sixers decided to bowl first in overcast conditions and it initially appeared a wise move. In a frenetic start, Heat opener Grace Harris was almost run out on the first ball of the innings before she succumbed next delivery to the steep bounce from left-arm quick Lauren Cheatle. Cheatle, who will be part of Australia's upcoming tour of India, bowled superbly with the new ball and exploited a surface that produced tennis ball-like bounce.

Heat struggled to adjust to the conditions and their inability to hit boundaries in the powerplay resulted in Bess Heath and Georgia Redmayne holing out tamely to full tosses.

But Perry had her revenge when she held on to a sharp return catch to end du Preez's breezy 42 off 27 balls. The wicket failed to halt Kerr, who put the foot down in the power surge and smashed left-arm spinner Linsey Smith for four consecutive boundaries in the 17th over.

Rather than hitting hard, Kerr focused on placement as she expertly unleashed a succession of shots piercing the gaps on the off-side.

Kerr, who had only made 62 runs in her last five innings, powered past her half-century along the way while big-hitting Charli Knott made 29 off 10 balls at the death. The pressure went on to Sixers' struggling top order, who had to curb wild swing from seamer Nicola Hancock.

They had luck go their way when Perry was dropped by Jonassen in the first over. She appeared to make Heat pay as Perry clubbed Knott's offspin for 18 runs in the next over in an ominous sign.

But in the third over Perry was caught behind after driving loosely leading to the arrival of struggling Suzie Bates. A couple of lusty blows powered her past 20 for just the third time this season, but she couldn't kick on and fell to Jonassen on 26.

Similarly to Bates, Erin Burns has had a lean season with her highlights confined to spectacular fielding. She launched the spinners over deep midwicket to devastating effect and combined in a 61-run partnership with Gardner.

The momentum was tilting towards Sixers with their cause aided by Kerr being penalised five runs for catching a return throw with the towel she was using to dry the ball.

Burns and Gardner holed out in the space of three deliveries before Carmichael and Brown's 51-run partnership breathed life into Sixers' season.