Sunrisers chased down a target of 212 set by South East Stars, reaching 121 for 3 with Griffith top-scoring with 57. South East Stars had Davidson-Richards leading the way with 93, but Coppack's 4-27 restricted them to 212. Sunrisers won by 27 runs via the DLS method.
Sunrisers completed their turnaround from perennial wooden spoon winners to become the last-ever regional winners of the Rachael Heyhoe Flint Trophy.
Sunrisers failed to win a match in the first three editions of the competition - first held in 2020 - but Kate Coppack's 4 for 27 and Cordelia Griffith's half-century set up a 27-run DLS victory over South East Stars.
Coppack's career-best ripped out the Stars top order to leave them 53 for 4, but Alice Davidson-Richards formed half-century partnerships with Aylish Cranstone and Phoebe Franklin on her way to 93.
Stars eventually reached 212, which Griffith attacked with her fourth fifty in her last five innings - and by the time the rain came they were on 121 for 3 and comfortably ahead of the 94 DLS par score.
It meant Sunrisers were the last to win the tournament in this format, with counties replacing the regions and the Metro Bank One-Day Cup becoming the women's 50-over competition in 2025 - although they will still compete to lift the Rachael Heyhoe Flint Trophy.
Sunrisers stuck Stars in and proceeded to dismantle their top order - specifically through the uber-accurate Coppack, who returned her Rachael Heyhoe Flint Trophy best of 4 for 27.
Coppack is one of the game's most interesting characters. A full-time lawyer, she has played international cricket for Peru and her parents own an alpaca farm. But first and foremost she is a deadly new-ball bowler.
The ball to bowl Alexa Stonehouse was seam-bowling perfection, as it kissed the top stump, even if the big hooping inswinger to castle a swinging Paige Scholfield was more aesthetically pleasing.
She hit the stumps again, this time to run out Bryony Smith after a mix-up with Davidson-Richards, before pinning Kira Chathli in front an over after the powerplay had ended.
Coppack's exit from the attack after an opening spell of 3 for 17, saw Davidson-Richards flourish into a partnership with Cranstone. The stand, eventually worth 70, was built on Davidson-Richards' ability of knowing when to use her power and when to push the runs on an expansive outfield.
She reached a fourth successive fifty with the former tactic, a picked-up ping through midwicket, in 61 balls. But at the other end, Cranstone was stumped - injuring herself in the process of sprawling backwards and requiring assistance to return to the dressing room.
Phoebe Franklin followed in Cranstone's footsteps to provide the company for Davidson-Richards to thrive. But Coppack's return saw the back of Franklin - bowled after a well-made 33 - and began the collapse which saw the last five wickets fall for 39 runs, as Davidson-Richards ran out of partners.
Ryana MacDonald-Gay and Tilly Corteen-Coleman were carelessly run out, Kalea Moore was lbw and eventually Davidson-Richards ran out of steam seven runs shy of a second Stars century when Mady Villiers dismissed her leg before.
Sunrisers' response started abysmally as Jo Gardner was lbw to teenager Corteen-Coleman for a golden duck. But from there the in-form Griffith saw the ball like a pumpkin with a series of increasingly middled shots to the boundary.
Her 54-ball fifty saw caressed cover drives, pumped pulls and sweeps to the boundary, as Grace Scrivens largely just passed over the strike in their 79-run stand.
Griffith, a Sunriser since the beginning, departed when she chased a wide Moore delivery to cover before the spinner got one to stick in the pitch to have Jodi Grewcock caught and bowled.
About a quarter of an hour later, and 25 overs into the innings, and lighting in the area took the players off, before torrential rain turned the outfield into a lake. At 4.20pm it was called off and Sunrisers had completed their zero-to-hero arch.