The Perth Scorchers have pulled off a bowling masterclass, defending their paltry 108 in a pulsating two-run, final-ball victory over the Melbourne Renegades at the WACA Ground.

And in Thursday's other game in Perth, England star Heather Knight cracked an unbeaten half-century and Sam Bates snared 4-25 to lead the Sydney Thunder to a 19-run victory over the Brisbane Heat.

The Scorchers crashed to 5-37 as the likes of Sophie Devine (0), Beth Mooney (8) and Dayalan Hemalatha (12) fell cheaply.

Handy knocks from Mikayla Hinkley (32 off 37 balls) and Alana King (23 off 15) helped the Scorchers post 108 from 19.5 overs.

Renegades all-rounder Alice Capsey snared three wickets in the final over to finish with figures of 5-25, while Milly Illingworth (2-15) and Hayley Matthews (2-15) helped spark the early collapse.

The Renegades stumbled to 2-1 and 6-58 in a disastrous start to their run chase.

Deandra Dottin (40 off 27 balls) looked set to be the match-winner before falling to King (3-23), and then it was Sarah Coyte (20no off 31 balls) who threatened to get the Renegades over the line.

The Renegades were eight wickets down and needing eight runs off the final over to secure victory.

If they had lost another wicket then the injured Emma de Broughe - who rolled her left ankle while fielding earlier in the match - would have come out with a runner.

Scorchers speedster Ebony Hoskin was entrusted with the final over, and it came down to the last delivery, with Coyte needing a four to win it or three runs to level the scores.

Coyte got an inside edge to Hoskin's delivery and Scorchers wicketkeeper Amy Jones did well to get down low to block the ball racing to the boundary.

The Scorchers' win marked the fifth lowest total successfully defended in WBBL history, with the Renegades finishing on 8-106.

"The heart rate was definitely high. That's an unbelievable win for us," King told Fox Sports after her player-of-the-match performance.

"We were really short with the bat. For us to defend that - how good was Ebs in the last over? Credit to her.

"I'm so proud of this group."

Perth (3-1) are second on the ladder, with the Renegades 2-3) fifth.

In Thursday's first match, Knight (59no off 34 balls), Phoebe Litchfield (40 off 25 balls) and Chamari Athapaththu (33 off 25 balls) all fired to lift the Thunder to a formidable 5-170.

In reply, Charli Knott (55 off 37 balls) and Grace Harris (41 off 31) threatened to pull off the run chase, but the Heat were eventually bowled out for 151 in 19.1 overs after Bates weaved her magic.

The result ensured the Thunder (3-1) remain on top of the ladder, while the Heat slipped to a 2-3 record.

Knott cracked six fours and a six to notch her maiden WBBL half-century and give the Heat a chance, but Brisbane's victory hopes came crumbling down when she was bowled by Bates.

Bates now has 12 wickets from four games in what has been a sizzling start to the season for the 28-year-old.

"I don't know if there's a real secret behind (my form). It's nice to be contributing finally," Bates told Fox Sports.

"I had a pretty ordinary season last year, so I reflected quite a bit on that.

"I changed some little things and they're paying off, which is nice."