A brilliant career-best 162 from skipper Kathryn Bryce helped Lightning end Central Sparks’ hopes of avoiding the play-off round in their bid to reach the final of the Rachael Heyhoe Flint Trophy.
The Scotland captain shared a 207-run stand with her younger sister, Sarah, as the Lightning posted a season-high total of 320-6.
Eve Jones (60) and Marie Kelly (62) both hit half-centuries in reply but the Sparks fell 25 runs short in their pursuit, finishing on 296-9.
“I’m delighted to put in a performance, especially first innings to really set up the game,” said Kathryn Bryce.
“It was a pretty good wicket and I felt really good from early on.
“Sarah and I have made runs together before at different levels but this is the first time we’ve put together a really big partnership at this level. It is easy to bat with Sarah because we understand each other’s games pretty well.
“Obviously there was not a lot to play for at the end of the season but it is great to finish on a winning note after a bit of a mixed season. It gives us more motivation going into the winter and shows us what we can actually do.”
The 207-run stand between the Bryces for the second wicket is the highest of this season’s competition.
Sarah was dropped on five but made the most of her good fortune, following her unbeaten 136 against Sparks last season with 90 off 104 balls, hitting 11 fours and a six before she fell to a fine one-handed catch by Issy Wong at mid-off.
Having completed her maiden List A hundred from 126 balls, Kathryn – who also captains Scotland Women – added another 61 from the next 30, racking up 21 fours and two sixes, batting for just short of three hours.
Lightning lost a wicket in the third over when Bethan Ellis was caught behind, Sarah Bryce having been put down at square leg in the previous over.
The Bryce sisters dominated for the next 36 overs before Sarah’s demise, after which Abbey Freeborn, Beth Harmer and Ella Claridge all fell cheaply.
But Sonia Odedra helped Kathryn Bryce add 63 in the last five overs, including 35 from the final 12 deliveries before the latter’s magnificent effort ended when she was run out off the final ball of the innings.
Jones and Kelly – dropped on 24 off Odedra – gave the Sparks’ chase the early momentum required, putting on 119 in 23.5 overs before the latter was superbly stumped off Yvonne Graves.
Jones was caught behind off England left-arm spinner Kirstie Gordon, who increased her tally to 16 as the competition’s leading wicket-taker.
Gwen Davies made 41 off 30 balls with four fours and two sixes but the pressure to score quickly inevitably cost Sparks wickets, Gordon, Odedra and Grace Ballinger picking up to each.
Vipers, who came out on top at the Ageas Bowl, now go through directly to next Saturday’s final at Northamptonshire’s County Ground, while Sparks and Diamonds must play off on Wednesday to decide who joins them.
The Lightning’s third victory of the tournament sees them finish fourth.