All-rounder Heather Graham top-scored with 35 from 32 balls as Durham squeezed over the line in a tense finish to stun Vitality Blast favourites Hampshire Hawks and reach the final at the Kia Oval.
Hollie Armitage and Mady Villiers shared an opening stand of 52, but Graham’s knock proved vital as Durham – who finished fourth in the table – slid to 78 for four in pursuit of their 130 target.
Having reached 49 for one after being put in, Hampshire shed wickets at regular intervals and needed Naomi Dattani’s unbeaten 28 from 22 to usher them to a competitive total at 129 for eight, with Sophia Turner taking three for 21.
But it was not enough and Grace Thompson (17 not out from 14) sliced Poppy Tulloch to the boundary to clinch victory with four balls to spare and set up a final against The Blaze.
Maia Bouchier returned at the top of the Hampshire order following Test duties, but her stay at the wicket proved a brief one, with Trudy Johnson having her caught behind off a thin edge for seven.
Ella McCaughan (23 from 16) looked nicely set, crashing a trio of consecutive boundaries off Villiers only to be unseated by Armitage’s smart diving catch at mid-off – the first of three wickets in nine balls.
The third of those, a pinpoint direct throw by Lauren Filer to run out Abi Norgrove, left the Hawks floundering at 55 for four and they never fully recovered, with batters continuing to depart after promising starts.
As well as pocketing their chances, Durham also reviewed wisely, overturning an initial not-out decision to have Amanda-Jade Wellington caught behind reverse-sweeping the miserly Katie Levick (one for 18).
However, Dattani managed to raise the tempo during the final over of the innings, which brought Hampshire a valuable 11 runs and set Durham a required rate of exactly six and a half.
Armitage (23 from 19) seized the initiative at the start of the chase, paddling Dattani twice to the fence before Villiers (25 from 27) overtook her partner by dispatching successive Georgia Adams deliveries for six and four.
Dattani achieved the breakthrough after switching ends, with Armitage’s fondness for the paddle bringing her downfall as she failed to connect and was bowled – and Tulloch’s second ball stayed low to hit Villiers’ middle stump in the next over.
Hampshire hopes were lifted by capturing another quick pair of wickets, with Bess Heath given out on a review to a bat-pad catch and former Hawks batter Emily Windsor punching Tulloch straight to cover.
McCaughan’s arrow throw from long-off left Mia Rogers short of her ground and, although Thompson eased the pressure by slamming back-to-back fours off Bex Tyson, Graham holed out to mid-off with 12 still needed.
Turner’s straight-driven boundary off Adams brought the target down to four from the final over and she and Thompson scrambled their side home.