Brisbane Heat 3 for 179 (Johnston 54, Voll 40) beat Melbourne Stars 8 for 170 by nine runs

Nineteen-year-old Brisbane Heat opener Ellie Johnston plundered four sixes during a powerhouse performance to help her side to a thrilling nine-run win over Melbourne Stars.

The clash was still in the balance until the final over when Heat captain Jess Jonassen picked up three crucial wickets after Annabel Sutherland had plundered 45 off 22 balls to leave Stars needing 15 off 10 balls.

Player of the match Johnston only got a call-up due to a knee injury to Heat top-liner Grace Harris and she made the most of her chance.

"It was pretty surreal. It was my first hit of the season and I was seeing them like watermelons," Johnston told Fox Cricket after her knock.

Heat opener Georgia Redmayne and Georgia Voll made handy contributions to lift their side to an imposing 3 for 179.

Stars responded in style, with English opener Lauren Winfield-Hill blazing a superb 74. Heat's Kerr sisters - Amelia and Jess - took the key top order wickets but overall the home side were poor in the field, albeit hampered by a damp ball.

Stars allrounder Sutherland, who has been in outstanding form with the bat this series, got her side to within striking distance of victory as she took advantage of the power surge before Jonassen's heroics in the final over prevailed.