Scorchers survive Knight's 71 to stay unbeaten with a four-wicket win at the WACA

Perth Scorchers made it five wins from five at the WACA Ground, running down 160 with nine balls to spare after Heather Knight's 71 had threatened to carry Sydney Thunder clear

Sydney Thunder won the toss and chose to bat in the 18th match of the Women's Big Bash League, and for an hour the decision looked a good one. Knight struck 71 from 46 balls to lift the visitors to 159 for 5 from their 20 overs.

Perth answered with 160 for 6 in 18.3 overs, Chloe Piparo steering the winning boundary away three balls into the 19th to seal a four-wicket victory and preserve the only unbeaten record in the competition.

They did it without Beth Mooney, ruled out with injury, leaving Sophie Devine to captain the side and a largely untested middle order to find a way home.

Knight finds the gaps

Knight reached her fifty from 36 balls with nine fours, and finished with 12 boundaries in all, most of them placed rather than forced.

She added 100 in 70 balls for the third wicket with Anika Learoyd, who made 53, and the pair lifted the Thunder from an uncertain start into a position of control.

The stand ended when Alana King bowled Knight, and Perth squeezed the closing overs. Devine returned 1-23 from three overs, and Nadine de Klerk and Tahlia Wilson were left unbeaten on 8 and 1 as the innings closed.

One short of the Thunder's marker

Thunder coach Lisa Keightley had named scoring as the strength her side could lean on in Perth, saying before the match that they had "been consistently scoring 160+ runs".

They finished a single run short of it. A total of 159 was competitive at a ground where Perth had won four from four, but it left no margin once the chase settled.

Keightley had also acknowledged the results that brought her side west. "You never want to drop a couple games, however, there's a lot of positives about how we have played," she said.

Perth reshuffle without Mooney

Mooney's absence was confirmed the day before the match, with the experienced quick Taneale Peschel added to a 13-player squad that was otherwise unchanged. Peschel came in against the club she previously played for.

Devine took the captaincy in her place, having led the Scorchers before Mooney's appointment, and the burden of the chase spread through the order behind her.

Piparo and Ainsworth settle it

Perth reached 126 for 4 in the 14th over, needing 34 from 37 balls, before the game tightened. Fatima Sana fell for 0 from two balls to make it six down and bring the result back into question.

Piparo and Chloe Ainsworth then put on an unbroken 27 from 18 balls, each striking two fours. Ainsworth's boundary in the 18th over brought the target within touching distance, and Piparo's edged four finished it.

Lauren Bell was the pick of the Thunder attack at the death with 1-26 from 3.3 overs, but there was too little on the board to defend.

Five from five

The win was Perth's fifth in succession and their second over the Thunder inside a week, following a 17-run victory at Drummoyne Oval on 5 November.

Phoebe Litchfield's side, who brought in leg-spinner Hasrat Gill for Lucy Finn, again found a substantial batting effort going unrewarded.

Scorecard: Sydney Thunder Women 159 for 5 (Heather Knight 71, Anika Learoyd 53, Sophie Devine 1-23) lost to Perth Scorchers Women 160 for 6 (Chloe Piparo 20 not out, Chloe Ainsworth 15 not out) by four wickets at the W.A.C.A. Ground.