Northern Diamonds 215 for 9 (Winfield-Hill 65, Heath 44, Adams 3-34) beat Southern Vipers 213 for 9 (Adams 70, Bouchier 48) by two runs
Lauren Winfield-Hill and Linsey Smith made it third time lucky for Northern Diamonds as they finally beat Southern Vipers by two runs in a thriller at Lord's to get their hands on the Rachael Heyhoe Flint Trophy.
Diamonds had come up short against Vipers in the two previous finals, but Winfield-Hill hit 65 and Smith 27 in an opening stand of 83 to form the basis of their total of 215 for 9, Bess Heath later adding 44 while Georgia Adams returned figures of three for 34 and Paige Scholfield two for 36.
Adams then made 70 with the bat, while Maia Bouchier weighed in with a spectacular 48, but the spin wizardry of Smith (two for 24) and three victims behind the stumps for Winfield-Hill saw Vipers come up just short in a breathless finish.
The day also saw Charlie Dean playfully pretend to run Smith out at the non-striker's end during the Diamonds innings, evoking thoughts of her run-out by that means at the hands of India's Deepti Sharma in the ODI 24 hours earlier.
Winfield-Hill, the tournament's leading run-scorer, towered over the opening stages of the final. The England international drove the ball exquisitely, mainly through the off-side, one back-foot punch through cover a thing of beauty.
Fellow opener Smith should have been stumped by Chloe Hill after dancing the pitch to Charlotte Taylor, but the chance went begging. Taylor though would soon extract revenge, Smith chipping one back to the spinner.
Winfield-Hill pressed on to an elegant 50 with seven fours, but Hollie Armitage, like Smith, struggled to time the ball. Nevertheless, the score reached 114 for 1 before Armitage took an ugly swipe at Scholfield and was bowled.
A dramatic collapse was triggered as Sterre Kalis fell first ball, Scholfield finding movement off the pitch to take the ball between bat and pad and uproot the off-stump once more. Phoebe Turner survived the hat-trick ball only to miss a straight one from Taylor in the following over and disaster followed as Winfield-Hill's serene innings ended on 65, run out by Georgia Elwiss' return from cover. Four wickets had fallen for five runs in 17 balls and Diamonds were teetering on the brink.
Heath and Leah Dobson stopped the bleeding, slowly at first before acceleration came late in a stand of 85. Heath struck Georgia Adams for three boundaries in quick succession before becoming the first of a trio of late wickets for the Vipers' skipper, two coming off successive balls in the final over.
Chasing 216, Vipers lost Ella McCaughan to the miserly Smith and Elwiss was castled by a huge in-swinger from Lizzie Scott.
Bouchier led the fightback, hitting first Katy Levick back over her head for four before taking heavy toll of the spin of Leigh Kasperek as a 50 partnership with Adams rattled up in a hurry.
Diamonds needed inspiration but instead got a large slice of luck when Bouchier belted an Armitage full toss straight to Smith at cover.
That brought Windsor to the crease, who signalled her intent with a dreamy cover-drive for four, but Armitage would account for her too as she nicked one through to Winfield-Hill.
Dean though picked up where she left off with England 24 hours earlier as 13 came from Armitage's penultimate over and the pendulum appeared to swing back towards Vipers once again.
She was given a life on 26 in Armitage's next over when Levick grassed the chance at point. Fortunately, it wasn't costly as she would clout a Kaseperek long-hop down the throat of short mid-wicket with 53 still needed.
Adams remained having gone almost unnoticed to 50 with only one four, but when she was stumped by Winfield-Hill from the bowling of Levick 20 were needed from the final two overs.
Smith bowled Scholfield amid rising tension and 13 from the final over proved just too many.