Hampshire 290 for 6 (Adams 107*, Taylor 60*, Kemp 50) beat Surrey 287 (Chathli 81, Monaghan 55, Davies 4-39) by four wickets
Hampshire will face Lancashire in the final of the Metro Bank One-Day Cup women's competition after Georgia Adams' century bested Surrey in the gloom.
Captain Adams led from the front with an outstanding unbeaten 107 from 101 balls for her second ton for Hampshire, with Freya Kemp's ballistic half-century and Mary Taylor's match-securing 60 not out.
It meant that Surrey's 287, headlined by Kira Chathli's 81 and flanked by a fifty for Alice Monaghan, wasn't enough - as Hampshire booked their place in Sunday's final at Utilita Bowl with 17 balls to spare.
Hampshire are hoping for a Metro Bank double - with their men in final action the previous day - while Lancashire could add to their Vitality T20 Women's County Cup from earlier this season.
Surrey built their testing total around three substantial partnerships of 81, 89 and 60, with Chathli and Monaghan striking half-centuries.
Skipper Bryony Smith was classily castled by Freya Davies in the fourth over, but Monaghan - against her former team - and Emma Jones built the foundations.
The pair made their names as bowlers but have turned themselves into genuine top-order allrounders, with aggressive styles that pile the pressure onto the bowlers.
Jones was smartly caught behind by Rhianna Southby and Monaghan top-edged in quick succession, but Alice Davidson-Richards and Chathli restored batting supremacy in an innings-defining 89-run stand.
Davidson-Richards' off-stump was sent AWOL by Naomi Dattani, but Phoebe Franklin added another 60 with Chathli to lead the middle-overs charge.
She bullied the bad balls with eight boundaries, with her first One-Day Cup half-century coming in 55 balls, to add another cherry onto a fine personal summer.
Hampshire fought back in the backend of the innings to keep Surrey under 300, led by Davies' excellent 4 for 39 and Bex Tyson's 2 for 39.
The hosts always had the threat of rain hovering over the chase, with heavy dark clouds constantly threatening to dump on Utilita Bowl. As such, keeping up with the DLS par score was crucial, while wickets would be decisive.
Hampshire losing both openers inside four overs made the job immediately more difficult - Southby slapped to deep square leg, while Maia Bouchier was caught at mid-off a ball after being dropped at mid-on.
But Kemp arrived to turn the situation around. The England allrounder demolished 50 in 26 with a brutal display of hitting, with seven fours and a pair of sixes.
She got Hampshire 10 runs ahead of the par score, but when she was bowled going back to Kalea Moore, the par rocketed from 77 to 103.
Adams, who had simply given Kemp free rein, now took control and pulled her side back to within touching distance of the rate with her standard range of ground strokes and gap finding.
Abi Norgrove's tame chip to short midwicket once again put Hampshire 30 runs short, with play suspended for 20 minutes by rain.
Nancy Harman was leg-before on the other side of the delay, but Adams gained stickability from Dattani, with whom she put on 53, and then Taylor.
Taylor has continually proven herself a useful lower-order batter but belied her List A best of 21, and with the unflappable Adams, the pair strode to the winning line with a century stand.
It was befitting for Adams to cut the winning runs for her 11th boundary.
Adams - who won three Rachael Heyhoe Flint Trophy titles with Southern Vipers under the guidance of Charlotte Edwards, now the England Women's head coach - was keen to add more accolades with her new, rebranded team.
"We had so much success with the Southern Vipers but having the opportunity to get some silverware for Hampshire would be incredible," Adams said. "The team as gone through a bit of a transition. We lost our head coach at the start of the season and have a load of younger players who have put in shifts throughout the season."
She was also keen to ensure that the final provided a victorious swansong for Davies, who will retire after that match to pursue a career in law.
"In my head I said I didn't want to say goodbye to Freya Davies yet," Adams said. "She is retiring at the end of the season so let's give her a send off. Hopefully she can sign off by lifting a trophy in Hampshire colours. She has been an integral part of the group and been a legend for us since signing. She has been an amazing sounding board for me.
"We started our cricketing journeys together at Sussex. I have seen her blossom and thrive into one of English cricket's most versatile bowlers. It'll be sad to see her go but hopefully we can give her the send off she deserves."
