|Charlotte Edwards Cup Eliminator, Ageas Bowl|
|Northern Diamonds 135-6 (20 overs): Winfield-Hill 65, Armitage 25, Gunn 22*; Bell 1-15|
|Southern Vipers 117 (20 overs): Windsor 32; Gunn 4-26, Smith 2-18|
|Northern Diamonds beat Southern Vipers by 18 runs|
Northern Diamonds beat Southern Vipers by 18 runs to set up a final showdown with South East Stars in the Charlotte Edwards Cup at the Ageas Bowl.
Lauren Winfield-Hill helped Diamonds recover from a slow start, hitting a six and five fours in a 49-ball 65.
Hollie Armitage made 25 off 22 balls before a late cameo from Jenny Gunn (22 not out) helped Diamonds post 135-6.
Vipers soon fell behind the rate against disciplined bowling, limping to 117 all out despite Emily Windsor's 32.
The Diamonds face a quick turnaround, with little more than an hour before the end of their semi-final win and the scheduled start of the inaugural final (16:00 BST).
Vipers qualified for the semi-final as the best runners-up, but restricted Group B winners Diamonds to 30-2 after six overs as Lauren Bell (1-15) bowled Bess Heath and went for just 12 runs in her three powerplay overs.
Skipper Armitage shared a 59-run stand with Winfield-Hill who continued to anchor the innings and reached a well-paced half-century off 41 balls.
The England batter, making just her second appearance in the competition this season, was bowled chasing late runs, but Jenny Gunn plundered 13 from off the final over to cap a useful 14-ball unbeaten cameo of 22 and stiffen the Vipers target.
Without three England players, including the big-hitting Danni Wyatt, Vipers were unable to build momentum and partnerships after openers Ella McCaughan (13) and captain Georgia Adams (14) both fell within four balls.
Tight bowling, particularly from seamer Rachel Slater (1-18) and slow bowler Linsey Smith (2-18), built the pressure, sparking a steady flow of wickets, including the key scalp of England all-rounder Georgia Elwiss (9).
And with the rate climbing, Gunn then mopped up the lower order, bowling out Vipers with the final ball of the innings, to add figures of 4-26 to her decisive late flourish with the bat.
Player of the match Northern Diamonds batter Lauren Winfield-Hill:
"Winning the toss and batting first, we knew we'd have a good chance of getting in and posting a decent score.
"We felt if we could build partnerships, we would be able to hang in there and post a good score.
"We gave ourselves a chance and Jenny Gunn's big hits in the last over gave us the momentum.
"The bowlers then came along and backed that up for us."