England's Danni Wyatt starred to leave the Southern Vipers on the brink of the Charlotte Edwards Cup Finals Day as she fired 76 from 44 balls in a five-wicket win over Lightning at Trent Bridge.
Western Storm beat the Sunrisers by 32 runs in Taunton thanks to a superb half-century from skipper Sophie Luff, while Northern Diamonds claimed a 25-run victory over Thunder at Headingley to continue their push for a place on Finals Day.
The final game on Sunday sees Central Sparks face reigning champions South East Stars at Edgbaston.
Wyatt leads Viper to victory | Scorecard
Having won the toss and elected to bat, Lightning lost Tammy Beaumont for one early on before recovering momentarily through Marie Kelly as she hit 36 from just 12 deliveries.
Kathryn Brice (23) and Lucy Higham (31) helped keep things competitive after their side had found themselves 77-6, before Lightning were eventually bowled out for 141 in 19.4 overs.
Vipers lost just five wickets on their way to chasing down their target in the 17th over, Wyatt leading the charge with a 29-ball 50 and hitting 11 fours and a six before being caught by Beaumont.
She had previously been dropped twice on 61 and 65 in albeit difficult opportunities.
Georgia Elwiss impressed against her old side with figures of 3-28, while Lightning's Higham took 3-30.
Luff stars for Storm | Scorecard
Storm captain Luff rewarded her decision to bat first as she smashed 78 from 53 balls to help her side post an unassailable score of 169-5 against Sunrisers.
Within her knock she shared 69 and 70-run stands with Heather Knight (34) and Danielle Gibson (26), respectively, despite the efforts of Kelly Castle (2-16) and Mady Villiers (2-33) with the ball.
Sunrisers were dealt early setbacks in their chase as Mady Villiers went for a duck followed by Grace Scrivens for just four.
Naomi Dattani hit back with 53 from 51 balls and shared a 56-run partnership with Castle (40), however the Sunrisers came up short as they were dismissed on 128-6.
Gibson was a thorn with figure of 2-13 while Claire Nicholas also claimed 2-22 and a maiden from her four overs.
Diamonds overcome injury setbacks to beat Thunder | Scorecard
Hannah Jones collected 3-23 from four overs as the Diamonds made light work of thwarting Thunder's run chase in the absence of England's Lauren Winfield-Hill, Katherine Brunt and Nat Sciver.
The Diamonds lost Bess Heath for 13 followed by fellow opener Sterre Kalis, who top scored with 28 before being caught by Georgie Boyce off the bowling of Alex Hartley.
Hollie Armitage fell for 17 to the bowling of Emma Lamb shortly after, and Linsey Smith notched 25 until being bowled by Hartley to leave her team 113-7.
Hannah Jones tore through the lower order to amass 3-21 as the Diamonds were eventually bowled out for 124.
Thunder saw their hopes fade early on when Lamb (15) and Boyce (16) departed, and were all out for 99 in the 19th despite Danielle Collins; 26 and Phoebe Graham's 20 off 16 balls in an effort to stabilise the chase.
Katie Levick was 3-25 alongside Leigh Kasperek's 2-16.
The win lifted the Diamonds into second in Group B, sitting behind the Vipers with two games to play.
Cranstone fires half-century in Stars win | Scorecard
Aylish Cranstone logged an unbeaten 59 from 53 as the South East Stars beat the Central Sparks by 10 runs.
Cranstone led the way for her side to help post 148-6 after Sarah Glenn had threatened a lower total with bowling figures of 3-17.
A rain delay 3.3 overs into the Sparks' chase saw their target revised to 102 off 12 overs, Evelyn Jones offering early hope with 25 until she was caught by Alice Davidson-Richards off the bowling of Danielle Gregory, who claimed 2-6.
Six single-digit scores followed before Glenn (14) and Arlott (19) provided some tail end fight, only to run out of overs as Sparks closed on 91-7.