Sydney Thunder 125 (Knight 45, Day 4-35, McKenna 3-18, Sutherland 3-22) defeated Melbourne Stars 121 for 9 (Darlington 5-10) for four runs
Darlington’s wickets included Stars captain Lanning, who was caught for 19 the day after announcing his shock retirement from international cricket.
Lanning looked set to guide Stars to a much-needed victory, showing off her trademark cut shots and guiding the ball off stump with ease.
But when she managed a cut Darlington shot towards goalkeeper Tahlia Wilson, the Stars’ chase suddenly found itself in serious trouble.
Lanning has not set an end date for her franchise T20 career, but Stars now need to see the best of her in the final five games of this season. Placed seventh in the standings, they will probably need to win all of those matches to reach the final.
Darlington was the catalyst for the Thunder’s victory. He got England star Alice Capsey caught for 27, before dismissing Annabel Sutherland in the same manner.
The 21-year-old also bowled the ball of the day to dismiss Kim Garth for a golden duck, pushing it back from outside off stump to take mid-leg and leg.
And just when the Stars looked ready to claw their way into the game, Darlington trapped Maia Bouchier at the leg-side boundary for 23.
Having made his Australian debut aged 19, Darlington is now pushing for his first national selection in two years after taking 13 wickets in his last four WBBL games.
Teenager Rhys McKenna, in particular, bowled superbly for Stars, while Sutherland was 3 for 22.
The Thunder’s victory puts them back ahead of the Adelaide Strikers in first place, with six wins from seven games, after picking up the wooden spoon last season.