Southern Vipers 97 for 4 (Elwiss 38) beat Thunder 94 for 6 (Dean 3-16) by six wickets

The Southern Vipers are the first team through to Charlotte Edwards Cup Finals Day - and the final - after beating Thunder by six wickets under lights at Emirates Old Trafford, chasing 95 in 15.3 overs.

Vipers have qualified for the Northampton showpiece (June 11) with one Group B game remaining following a superb bowling and fielding display led by England off-spinner Charlie Dean, who returned three for 16 from four overs to limit their hosts to 94 for six.

Thunder included England trio Emma Lamb, Kate Cross and Sophie Ecclestone - the latter pair only just back from IPL Challenge commitments in India. But they were unable to break the shackles imposed on them by a team who have now won all five games in the competition named after their head coach.

None of the Vipers' five bowlers conceded more than 20 runs in their four-over spells, with left-arm seamer Freya Kemp also impressing with two for 20 before Georgia Elwiss top-scored in the reply with a measured 38 not out off 35 balls.

The Vipers have also qualified direct for the final a week on Saturday as the best of the two group winners courtesy of a five-point, bonus point win here.

They sit on 23 points, while Group A leaders Central Sparks have 17 with only five more points to play for.

This was a display from the Vipers which had all the hallmarks of a team who reached last year's Charlotte Edwards semi-final and are back-to-back Rachael Heyhoe Flint Trophy champions.

Thunder, who elected to bat, lost in-form openers Lamb and Georgie Boyce for five and nine as the score slipped to 44 for three after 10 overs.

Kemp had Lamb caught at mid-on and bowled Boyce. Sandwiched in between, Cross, promoted to bat at three, fell victim to a combination of England team-mates Dean and Danni Wyatt for 18.

Cross hoisted Dean out to deep midwicket, where Wyatt took a fine low catch on the run.

Ecclestone was also promoted to No.4 in a side who have struggled for middle-order runs through the competition.

She demonstrated her power by pulling her fourth ball for six over backward square-leg off Kemp as the score moved to 41 for two in the 10th over - shortly before opener Boyce's dismissal.

Unfortunately for Thunder, playing in the primetime slot on a T20 double-header day with Lancashire's men, there was no more acceleration.

While Ecclestone made 28 not out off 32 balls, she was unable to find the boundary again and saw canny Dean trap Danielle Collins lbw and get Thunder captain Ellie Threlkeld caught and bowled cheaply.

In all, Thunder only hit four fours and that Ecclestone six, while 21-year-old Dean has now taken eight wickets in her first three games of the summer. This was her best haul so far.

Determined to complete the chase in 16.1 overs to secure the bonus point win which qualified them direct to the final, visiting openers Wyatt and captain Georgia Adams were busy from the off.

Wyatt slog-swept Ecclestone for six over midwicket to advance the score to 22 without loss after three overs.

But there was a stumble as both openers fell in the space of four balls as the score slipped to 34 for two in the sixth over. Wyatt was stumped for 13 by Threlkeld sweeping at ex-World Cup-winning spinner Alex Hartley before Cross had Adams caught at cover for 17.

Another left-arm spinner, Hannah Jones, had Maia Bouchier caught and bowled before Threlkeld superbly stumped Kemp stood up to Laura Jackson's seam as the score fell to 75 for four after 13 overs.

But the presence of Elwiss ensured they were only minor blips, hitting five fours in her match-clinching innings.