Perth Scorchers 159 for 4 (Mooney 101*) beat Sydney Thunder 117 for 8 (Litchfield 45, Edgar 3-18) by 42 runs

Perth Scorchers usurped Sydney Thunder at the top of the table after Beth Mooney's third WBBL century powered her side to a 42-run win.

After losing her superstar opening partner Sophie Devine early, Mooney almost single-handedly steered Scorchers to a competitive 159 for 4 at the Junction Oval.

In reply, the resurgent Thunder fell to 18 for 3 by the end of the powerplay, having not dropped any wickets there in their previous seven games.

Young quick Chloe Ainsworth (2 for 8) set the carnage in motion with back-to-back wickets and things only spiralled further out of control from there.

The loss was only Thunder's second of the tournament and relegated them to second spot on the ladder behind Scorchers.

It was only in the twilight of the Scorchers' innings that Mooney enjoyed a steady partnership as in-form Hannah Darlington spearheaded the Thunder attack to keep her team-mates quiet.

Chloe Piparo did well to help Mooney steady the ship following the loss of Amy Jones just as Scorchers looked primed to take the power surge.

Mooney had played a patient innings but smacked Sammy-Jo Johnson for four fours from five deliveries in the final over to snatch the ascendancy for Scorchers.

On 97, Mooney pulled stand-in Thunder captain Johnson past deep midwicket for four to bring up an unbeaten ton on the last ball of the innings and the 61st delivery she faced.

Mooney is now the only player to have passed 400 total runs in all nine iterations of the WBBL and is the current edition's second-highest run-scorer, only one run behind Devine.

Thunder were in trouble by the end of the power play after Ainsworth snared star imports Chamari Athapaththu and Marizanne Kapp in consecutive balls.

Scorchers successfully reviewed an lbw shout on in-form Athapaththu before Piparo at point caught out-of-sorts Kapp for a golden duck.

Rested with hamstring soreness, captain Heather Knight watched on helplessly as the Thunder batting order fell to 33 for 5 when Devine caught and bowled Claire Moore.

Only Australian representative Phoebe Litchfield offered resistance at first drop so when she was caught in the deep from Amy Edgar's bowling, Scorchers were home.