Southern Vipers 295 for 5 (Knott 102, Adams 65) Western Storm 291 for 9 (Knight 62, Wilson 53, Luff 51, Gibson 51) by four runs

Charli Knott registered a superb career-best 102 from 112 balls as Southern Vipers held their nerve to beat Western Storm by four runs in a thrilling Rachael Heyhoe Flint Trophy contest at Bristol's Seat Unique Stadium.

The 21-year-old Australian all-rounder dominated stands of 91 and 115 with Maia Bouchier and Georgia Adams for the first and second wickets respectively as Vipers posted a formidable 295 for 5. Adams went onto score 65, while Freya Kemp smashed a quickfire 44 not out.

England captain Heather Knight and Fran Wilson laid the foundations for a successful chase, both registering half centuries in a third-wicket stand of 112 in 18 overs. Sophie Luff and Dani Gibson then staged an outstanding alliance of 78 in nine overs to set-up a dramatic finale. Both scored half centuries, only to be be dismissed with victory in sight, Freya Davies and Adams bowling well under pressure at the death to finish with two wickets apiece as Storm came up just short on 291 for 9.

Storm won the toss, inserted the Vipers and were then forced firmly onto the back foot as the visitors made the most of the fielding restrictions and some loose bowling to come flying out of the blocks. New ball bowlers Mollie Robbins and Gibson conceded too many four balls as Knott and Bouchier raised 50 in just 36 deliveries.

Queenslander Knott helped herself to 14 off the first over, sent down by Robbins, to set the tone, and continued to pierce the field at will. Playing positively from the outset, the 21-year-old raced to her half century from 37 balls, turning a delivery from Sophia Smale in front of fine leg to go to that landmark with her tenth four.

Skipper Bouchier was also severe on anything short of a length, harvesting seven boundaries and contributing a 43-ball 34 in a progressive opening stand of 91 in 13.3 overs before succumbing to Amanda-Jade Wellington's leg spin, miss-timing a drive and finding extra cover.

Any relief proved short-lived for Storm, Adams picking up where Bouchier had left off, scoring at nearly a run a ball to keep the pressure on the bowlers. The second wicket pair both treated Australian international Wellington with respect, but were able to milk the other bowlers, finding the gaps and running hard between the wickets to keep the scoreboard ticking over as the partnership realised three figures.

Vipers were 141 for 1 at the halfway stage and Adams, so often a thorn in the side of Storm ambition in recent years, went to 50 from 63 balls soon afterwards. Although unable to score as freely once the ball had softened, Knott continued to work the field on both sides of the wicket, pushing a delivery from Wellington in front of point and scampering a quick single to register her maiden hundred from 107 balls in the 35th over.

But the Storm bowlers retained their discipline, kept plugging away and were rewarded for their persistence when slow left armer Smale claimed the key wicket of Knott, who was bowled in the 38th over with the score on 206. England star Danni Wyatt came and went quickly, bowled by Alex Griffiths for 11, while Adams found Heather Knight at cover and departed for an 86-ball 65 as Smale struck another decisive blow. Charlie Dean then hit the returning Gibson to mid-off, at which point the champions had lost four wickets in eight overs for the addition of 39 runs.

That was the cue for Freya Kemp and Georgia Elwiss to adopt a high-risk approach and afford the innings much-needed late acceleration. Coming together with the score on 245 for 5 in the 46th over, these two threw caution to the wind in a high-octane unbroken stand of 50 from 29 balls.

Big-hitting Kemp proved especially destructive, smiting 5 fours and a six in an aggressive knock of 44 not out from 33 balls, Elwiss finding the boundary twice in a useful cameo of 18 from 10 deliveries as Vipers turned the screw.

In need of a good start, Storm instead failed to take advantage of the powerplay, losing openers Smale and Griffiths to England seamer Freya Davies inside 10 overs as the competition favourites stamped their authority.

Aware of the compelling need to redress the balance, the experienced pair of Knight and Wilson injected some urgency into proceedings, finding the boundary rope often enough to at least keep their team in contention. When Storm reached the end of the restrictions on 62-2 in the 15th over, they were 39 runs behind Vipers at the same point.

But while the two former England colleagues remained at large, Storm were in with a shout, and when they reached the halfway point on 125-2, requiring a further 171 runs to win at 6.84 an over, it was very much a case of game on. Knight raised an assured run-a-ball 50, while Wilson needed five deliveries more to attain the same landmark as the third wicket alliance entered three figures.

Just as Wilson and Knight were threatening to take the contest by the scruff of the neck, their partnership foundered on an instance of rare ill-fortune. When Wilson drove straight back at Davies, the bowler fortuitously deflected the ball onto the stumps with the unlucky Knight out of her crease. Their talisman run out for 62, Storm suffered a further blow six balls later, Wilson hoisting Dean straight to Wyatt at deep mid-wicket and departing for a 63-ball 53 as Storm slipped to 145 for 4 in the 29th over.

Undaunted by the task of scoring at eight an over, Luff and Nat Wraith advanced the score to 191, only for the latter to hoist Knott's off spin to deep mid-wicket and depart for 28. Gibson then picked up the cudgels, taking the same bowler for three boundaries in four balls in a bold statement of intent.

With 81 needed off the last 10 overs, Luff and Gibson targeted the spinners, matching one another blow for blow to put the Vipers under real pressure for the first time. Leading by example, Luff went to 50 via 47 balls, but was out for 51 when hitting Adams straight to mid-off in the 47th over with a further 27 needed off 23 balls.

Gibson reached 50 from 31 balls with 7 fours as the chase went down to the wire, but Davies held her nerve, conceding just six runs off the penultimate over. With 12 needed off the last, experienced campaigner Adams effectively finished the job, having Gibson held at mid-wicket off the second ball of the over, before Robbins was run out.