The Blaze claimed victory over group leaders Southern Vipers in a tight encounter at Arundel Castle Cricket Club.
Defending 208, the international experience of Orla Prendergast, on debut, Kathryn Bryce and Kirstie Gordon came to the fore to dismiss the hosts for 188.
The result maintains The Blaze’s fifth spot, with the top four going through to the semi-final, but shortens the gap to just four points.
At the start of the day, under sunny skies in Arundel, Sarah Bryce and the returning Georgie Boyce, stepped out to face the table-topping Southern Vipers.
The pair added a brisk 27 inside seven overs, before Freya Davies bowled The Blaze’s wicketkeeper for nine.
Boyce, back in the team after a lengthy battle with injury, would ultimately have to retire hurt on 17, having pulled up running a quick single.
Georgia Elwiss accounted for Kathryn Bryce (16), after the Scotland international had launched Linsey Smith for a straight six, before Ava Lee, on her 19th birthday, trapped debutant Orla Prendergast in front for 11.
With wickets falling around her, Marie Kelly had been making serene progress, striking seven boundaries in 37 balls, adding 40 runs to the total in the process.
However, the drinks break seemed to stifle her momentum, Georgia Adams removing the dangerous right-hander with the third ball after the resumption.
Ella Claridge (14) and skipper Kirstie Gordon (18) fell in the teens, to Adams and Lee respectively as Lucy Higham battled on at the other end.
Off-spinner Lee then combined with Linsey Smith on two further occasions, dismissing Josie Groves for 5 and Higham, following a well-made 29 from the all-rounder.
Boyce (27*), clearly struggling with her leg injury, valiantly hobbled her way to the middle, accompanied by Kathryn Bryce as a runner, to add a further 24 for the final wicket with Grace Ballinger (9).
Defending 208, Gordon’s side were in the market for early wickets, debutant Prendergast duly obliging by removing Ella McCaughan with just her fifth delivery.
The tall seamer added the crucial scalp of Vipers captain Adams for 14, before Gordon deceived Elwiss, whose stunning century was the difference in the reverse fixture, to have her caught and bowled for 12.
And when Prendergast and Gordon combined to run out Rhianna Southby for 36, the game was in the balance at the halfway stage, with either 111 runs or six wickets required for victory.
After the break, Emily Windsor and Abi Norgrove took the attack to the visitors, adding 56 for the fifth wicket.
Just as it looked the momentum was all with the hosts, Prendergast returned to the attack to dismiss Windsor (41) with her first delivery.
Three overs later, Mary Taylor (8) and Alice Monaghan fell in consecutive deliveries, ran out by McCarthy and spectacularly caught behind by Sarah Bryce, the hosts still 46 short of their total.
Sarah Bryce was once again in the action for the ninth wicket, taking a smart stumping off sister Kathryn, before the all-rounder put the finishing touches on a stellar victory, trapping Lee LBW for 0.
The Blaze return to home comforts next Saturday with the visit of the third-placed Sunrisers to the Incora County Ground in another crucial fixture in the hunt for the knockout stages.