Brisbane Heat 6 for 165 (Mooney 50, L Harris 36) beat Sydney Sixers 73 (Kerr 3-8) by 92 runs

Brisbane Heat backed up their championship-winning performance in last year's WBBL final by launching their title defence with a crushing 92-run victory over Sydney Sixers who slumped to their lowest ever total.

Beth Mooney struck a half-century but the game-changing innings came from Laura Harris who arrived at No. 8 and hammered 36 off 17 balls to give a late surge to a Heat batting display which had spluttered after a strong base in the powerplay.

She dominated a seventh-wicket stand of 50 off 24 balls with Mikayla Hinkley which included Harris' onslaught that brought 25 runs off the 18th over.

The Heat then made crucial inroads into the strong Sixers top order as Sammy-Jo Johnson removed Alyssa Healy and Ash Gardner to take out two of the power hitters. The loss of Ellyse Perry in the 13th over was curtains for the Sixers and the tail folded to the variations of New Zealand legspinner Amelia Kerr who landed her googlies perfectly on WBBL debut. In a dramatic slide, the last six wickets fell in the space of 14 balls.

The Sixers, who opened the tournament with a strong performance against Sydney Thunder, were off colour from the start of the match with a lethargic display in the field which enabled Mooney, who was dropped at cover on 4, and captain Kirby Short to add 51 before Lauren Smith sparked the Sixers with a smart run out to remove Short.

The innings then slipped with Grace Harris run out in a mix-up with Mooney and Hayley Silver-Holmes picking up a brace of lbws. As usual, Healy was sharp behind the stumps with her dismissal of Mooney especially swift although Healy was back in position for the next delivery when it became clear the batter was out.

That left the Heat 6 for 115 and in need of a late charge which Laura Harris provided as she targeted the leg side with hefty slog-sweeps.

Healy looked in the mood to take charge of the chase, striking the ball cleanly one again, but picked out mid-off in the fourth over where Laura Harris kept her cool to take a juggling catch at the third attempt.

Her sister, Grace, then held a well-struck shot by Gardner at cover which was followed by Erin Burns top edging an attempt to lap-sweep Delissa Kimmince which left the innings on Perry's shoulders. She couldn't get going amid the loss of wickets and eventually picked out long-on in the 13th over from Jess Jonassen who removed Maddy Darke two balls later.

Kerr then ripped through the tail with three wickets in four balls in the 14th over and was within a whisker of a hat-trick when No. 11 Stella Campbell shouldered arms to another googly.

Andrew McGlashan is a deputy editor at ESPNcricinfo