The Heat were forced to back up after their Saturday night game for the 9.15am start local time on Sunday and while they elected to bat first, they struggled against an in-form Strikers bowling unit, restricted to 7-94 from their 20 overs.
Heat quick Courtney Sippel struck twice in as many balls in the second over to remove South Africans Dane van Niekerk (5) and Laura Wolvaardt (0) and give her side hope of defending the low total, but Katie Mack (54no from 48) and Tahlia McGrath (31no from 44) combined in an unbeaten 88-run stand to see the Strikers home with 22 balls to spare.
Mack looked confident and assured at the crease as she struck eight boundaries to register her second half-century of the tournament.
Her knock was was the first score above 50 for the weekend's three matches in Mackay, which had been dominated by the bowlers.
The Heat were kept to 1-26 in the powerplay and leg-spinner Amanda-Jade Wellington reaped the rewards when she entered the fray, dismissing Georgia Redmayne (14) and Georgia Voll (12) in the same over.
Mikayla Hinkley (15 from 29) and Jess Jonasssen (13 odd 20) struggled to keep the score ticking along, but the aggressive Laura Kimmince provided a much-needed late cameo, hitting one six and two fours in an unbeaten 22 off 11.
Both teams are likely to remain in the top four, with one week of regular season games remaining, but the battle for the top two will be critical given the WBBL's new finals format.
The side finishing on top advances directly to the final, while third and fourth will need to play off in an eliminator before the winner of that game takes on the side finishing second.
Home finals (borders permitting) are also up for grabs for the top two teams.