Going into the final over still needing 12 runs, Ecclestone - the England spinner - smashed a six and a four, before hitting the over's third ball for two to win the game
Sydney: Brisbane Heat 163-5, Sydney Sixers 164-5 - Sydney Sixers win by five wickets
Sophie Ecclestone starred with the bat as Sydney Sixers stunned Brisbane Heat to come back from the dead to strengthen their spot at the top of the table and seal their place in the playoff stage.
Sixers had been reduced to 72 for 5 in pursuit of 165 for victory, only for the English left-arm spinner – who was unusually expensive with the ball earlier in the evening – to smash 47 off just 25 balls, including a six and a four in the final over, which began with Sydney still needing 12 runs to clinch a thriller.
Needing 92 runs in the last eight overs with five wickets remaining, Ecclestone and Erin Burns (51*) pulled off a remarkable heist with three balls remaining after Alyssa Healy (6) and Ellyse Perry (0) – both so good in Sixers' similarly big chase against Perth Scorchers a matter of days earlier – had fallen to Nicola Hancock and Jess Jonassen inside the first four overs.
Ash Gardner then departed for 15, with Suzie Bates the glue that was holding together a star-studded line-up. But she was caught and bowled by New Zealand teammate Amelia Kerr for 41 in the eleventh over, at which point the game appeared up, particularly when Nicole Bolton was run out by Grace Harris seven balls later.
Ecclestone leaps for joy after hitting the winning runs for Sixers (Jason McCawley/Getty Images)
But that was to be Heat's last success as what began as a counterattack became a match-winning, unbroken partnership that left Sixers' players jumping for joy in the dugout as Ecclestone's firm drive towards deep extra cover brought final two runs needed to complete a stunning win.
Earlier, Danni Wyatt (31) and Georgia Voll (21) had given Brisbane the perfect start, with Wyatt hitting Lauren Cheatle over her head for six in the opening over of the match and only falling when she had done her job and Heat were closing in on fifty in the fifth over.
Brisbane lost their way thereafter – none of Voll, Georgia Harris nor Laura Harris scored at better than a run a ball as Kate Peterson claimed figures of 4 for 17 – but a superb late charge from Jess Jonassen, who struck six fours in her 21-ball 38, ensured that Heat made 62 runs off the last 28 balls of their innings.