RACHEL Priest smashed a blistering half century as Western Storm beat Lancashire Thunder by five wickets at Bristol to book their place at finals day in the Kia Super League.

The big-hitting New Zealand international raised 52 from 26 balls and dominated an opening stand of 60 with captain Heather Knight as Storm chased down a target of 123 with 2.5 overs to spare.

Their qualification for finals day at Hove next Friday was confirmed when news filtered through from Arundel that defending champions Southern Vipers had beaten Yorkshire Diamonds.

Having registered a superb hundred in a winning cause against Diamonds at York last weekend, Priest carried on where she left off, raising 50 from 22 balls and harvesting 7 fours and 3 sixes in a whirlwind innings that put bottom-of-the-table Thunder to the sword.

Knight, fellow England World Cup winner Fran Wilson and West Indies all-rounder Stafanie Taylor came and went in quick succession, while Priest departed in the eighth over, as Storm slipped to 73-4. But Sophie Luff held her nerve to post an unbeaten 24 and calm fraying nerves as Storm reached their target without any further drama.

Beaten in all four of their previous outings, Thunder were determined to make amends by causing an upset against last season's losing finalists. Amy Satterthwaite and Emma Lamb certainly did their best to restore red rose pride in a revitalising stand of 69 in 12 overs for the fourth wicket as the visitors recovered from 41-3 to post 122-5.

Experienced New Zealand international Satterthwaite seized the initiative, top-scoring with 44 from 41 balls and taking advantage of short boundaries to plunder 5 fours and a six.

She received staunch support from Emma Lamb, who was prepared to rotate the strike and play second fiddle in an unbeaten knock of 30 from 43 deliveries.

Satterthwaite had a half century in her sights when when she took one liberty too many against the nagging accuracy of Freya Davies and succumbed to a smart stumping at the hands of Kiwi compatriot Rachel Priest in the penultimate over.

The pick of the bowlers, Davies returned figures of 2-24 from four overs, while Stafanie Taylor, Knight and Jodie Dibble took the pace off the ball to restrict scoring in the middle overs.