Sunrisers 234 for 3 (Griffith 68, Grewcock 63*, Scrivens 56) beat Northern Diamonds 232 for 8 (Marlow 63, Kalis 49, Turner 32*) by seven wickets
Half-centuries from captain Grace Scrivens, Cordelia Griffith and Jodi Grewcock steered Sunrisers to a maiden Rachael Heyhoe Flint Trophy final appearance as they chased 233 to beat 2022 champions Northern Diamonds by seven wickets in a one-sided semi-final at Headingley.
Sunrisers will meet South East Stars in next Saturday's final at Leicester.
Sunrisers held firm in a contest which swung back and forth, with opener Scrivens posting 56 off 73 balls, Griffith 68 off 89 off and Grewcock 63 not out off 68. The latter two posted season's-best scores as victory was sealed in the 44th over.
Diamonds, aiming for a fourth 50-over final in the five-year regional era, posted 232 for 8 thanks to opener Emma Marlow's measured 63 added to 49 from Sterre Kalis and a late 32 not out from 15 balls for Phoebe Turner.
Six of the seven bowlers employed by Scrivens, including herself, struck before she confidently laid the platform for a chase all but finished off by a 134-partnership for the third wicket between Griffith and Grewcock. It was their region's highest of the season.
Having elected to bat, the Diamonds innings was built around a solid start and a blistering end.
Marlow shared in two early partnerships of substance - 48 for the first wicket with Lauren Winfield-Hill and 42 for the third with Kalis, who was run out at the end of the penultimate over.
When Marlow fell, caught and bowled by new ball seamer Kate Coppack as the score fell to 119 for 3 after 29 overs, Sunrisers put the squeeze on impressively.
Coppack was excellent in conceding only 29 runs from her 10 overs, while leg-spinner Grewcock also struck once and was nearly as miserly as she conceded 26 in eight overs.
Coppack's new-ball partner Eva Gray struck twice with her lively seamers, getting Erin Burns caught at mid-off and Abi Glen caught at short third as the score fell to 185 for 7 in the 47th over.
Led by Phoebe Turner, Diamonds then counter-attacked as she crashed five boundaries in her cameo, including four of them off Gray as the 49th over cost 20.
Key seamer Sophie Munro only bowling two early overs, including the wicket of Rebecca Duckworth caught behind, before leaving the field injured hurt Sunrisers on a sunny Headingley day. But they cruised with the bat.
Sunrisers have now won eight RHF Trophy matches this season. In the first four seasons of regional cricket, which started in 2020, they only won six combined.
Scrivens shared an opening partnership of 70 in 14 overs with Jo Gardner, which included the former hoisting the off-spin of Australian all-rounder Burns for six over wide long-on.
After Gardner had been trapped lbw by Beth Langston for 19, Scrivens reached her fifty off 66 balls - her fourth added to a century in this campaign.
Her haul of 514 runs is the second best in the competition.
However, the left-hander was trapped lbw by Katie Levick's leg-spin not long afterwards, leaving Sunrisers 91 for two in the 19th over.
From there, Griffith took on the senior role to steer the chase, with one late cut for four off Levick particularly memorable. She also clubbed a Rachel Slater full toss over square-leg for six.
By the time she reached her fifty off 64 balls, Sunrisers were all but over the winning line at 181 for two in the 36th over.
Grewcock rubber-stamped things with a 54-ball fifty, effectively ending the Diamonds existence given their players will now head to pastures new following the domestic restructure ahead of 2025.
Levick trapped Griffith lbw, but it was nothing more than consolatory as Sunrisers get one last dance.