Knight's 71 is not enough as Piparo and Ainsworth see the Scorchers home at the WACA

Perth chased down 160 with nine balls unused to make it five wins from five, despite a third-wicket stand of 128 between Heather Knight and Anika Learoyd

The Perth Scorchers beat the Sydney Thunder by four wickets at the W.A.C.A. Ground on Wednesday, reaching 160 for 6 in 18.3 overs and stretching their unbeaten start to the WBBL|12 season to five matches.

Knight made 71 from 46 balls and Learoyd 53 from 44 after the Thunder had slipped to 18 for 2, but the visitors managed only 13 runs from the last 13 balls of their innings and closed on 159 for 5.

Perth lost four wickets for 47 runs in the middle of the chase before Chloe Piparo and Chloe Ainsworth saw them home with an unbroken stand of 27.

Thunder rebuild from 18 for 2

Georgia Voll went in the opening over for a five-ball duck, caught by Mikayla Friday off Chloe Ainsworth, and Phoebe Litchfield followed in the fourth, caught by Freya Kemp off Fatima Sana for 13 from 14.

That left the Thunder 18 for 2 and brought Knight and Learoyd together. The pair batted into the 18th over, adding 128 for the third wicket and taking the innings past 140 without further loss.

Knight, the England batter, was the quicker of the two, striking at 154 to Learoyd's 120.

Perth take three in the last 13 balls

At 146 for 2 with 13 balls left, the Thunder looked set for a total beyond 170. Alana King bowled Knight with the fifth ball of the 18th over to end the stand.

Sophie Devine had Learoyd caught by Sana at the start of the next over, and Amy Edgar removed Laura Harris for 3 in the final over. The last 13 deliveries brought 13 runs and three wickets.

Five of Perth's six bowlers took a wicket, and none conceded more than 30: Ainsworth 1-22, Devine 1-23, Edgar 1-24, Sana 1-26 and King 1-30, with Lilly Mills going wicketless for 29.

Devine and Mack set up the chase

Ines McKeon was lbw to Sam Bates in the first over of the reply, leaving Perth 7 for 1 inside three balls.

Sophie Devine, captaining in Beth Mooney's absence, then added 79 for the second wicket with Katie Mack. Devine made 37 from 32 before Nadine de Klerk bowled her at 86, and Mack fell for 31 from 27, caught and bowled by Jemma Barsby an over later.

The Thunder kept striking. Lauren Bell had Kemp caught by Harris for 10, Friday was run out by de Klerk for 24 from 16, and Hannah Darlington bowled Sana for a duck to leave Perth 133 for 6 in the 16th over, still 27 short.

Piparo and Ainsworth finish it

With 27 needed from 27 balls and four wickets in hand, Chloe Piparo and Ainsworth took the game away from Sydney without a scare.

Ainsworth, who had opened the bowling, made 15 not out from eight balls, and Piparo finished unbeaten on 20 from 16 to bring up the win with nine balls to spare.

Mooney out, Devine in charge

Perth were without Mooney, their full-time captain and the WBBL's record-holder for half-centuries, who was ruled out with an injury the club did not detail. Taneale Peschel came into an otherwise unchanged 13.

Sydney made one change, bringing in leg-spinner Hasrat Gill for Lucy Finn. "Hasrat has been bowling extremely well at training. She gives us another option leading into a big game tomorrow," head coach Lisa Keightley said when the squad was named.

Keightley had named the problem her side ran into again at the WACA. "We've been consistently scoring 160+ runs and I think if we can extend our partnerships and have a set batter going into the death overs, we can even stretch that further," she said.

It was the second meeting between the teams in a week, after Perth won by 17 runs at Drummoyne Oval on 5 November. Defeat was the Thunder's third in a row, following a nine-run loss to the Sydney Sixers under the Duckworth-Lewis-Stern method on Sunday.

Scorecard: Sydney Thunder Women 159 for 5 in 20 overs (Heather Knight 71, Anika Learoyd 53) lost to Perth Scorchers Women 160 for 6 in 18.3 overs (Sophie Devine 37, Katie Mack 31) by four wickets at the W.A.C.A. Ground, Perth.