Emma Marlow scored her professional best 71 but Ellie Anderson claimed career-best List-A figures as Somerset beat Durham by three wickets at the Cooper Associates Ground.
The former England Under-19 seamer took 5-40 to restrict Durham to 248-9, while Lola Harris weighed in with 2-53. Emma Marlow posted 71, Eleanor Larosa hit a quickfire 44 and Grace Thompson scored 41 as the visitors recovered from 95-5.
Charlie Dean and Niamh Holland masterminded the chase, posting 76 and 70 respectively and staging a superbly-judged stand of 104 as the home side reached their target with 5.2 overs to spare.
Somerset won the toss and Anderson accounted for Mia Rogers, Hollie Armitage and Mady Villiers in a devastating new ball spell of 3-25. Marlow and Danielle Collins added 36 for the fourth wicket, but Chloe Skelton had Collins held at point and Harris induced Bess Heath to hit to mid-wicket.
Adopting a high-risk strategy and riding their luck on occasion, Thompson and Marlow had advanced the score to 163 by the time Harris persuaded Marlow to hole out to long-off.
There was no respite for the home side as Larosa launched a fearsome assault, the South Australian striking the ball cleanly in raising six fours and a six in a whirlwind knock of 44 from 31 deliveries. The Adelaide Strikers all-rounder had contributed 41 in a partnership of 51 in 6.2 overs with Thompson when she chopped on to the returning Anderson.
Sophie Luff ran out Thompson and Anderson then cleaned out Katherine Fraser to become the first female Somerset bowler to take a List-A five-for in the professional era.
Somerset openers Luff and Bex Odgers fell to Larosa and Lauren Filer respectively as Durham made inroads with the new ball, while Katie Levick bowled Emma Corney for 22 and Villiers had Gibson held at extra cover as spin further reduced the home side to 84-4.
Holland and Dean dug in thereafter, finding the gaps, running hard between the wickets and punishing the poor ball when it came along to post a 50 partnership via 48 deliveries. Holland went to a methodical half century from 68 balls, while the more aggressive Dean faced 19 deliveries fewer to reach the same landmark as the partnership realised three figures.
Holland’s 90-ball innings was terminated in the act of slog-sweeping Fraser to mid-wicket, while Filer removed Jess Hazell for 17 with the score 217-6. But Dean remained at large long enough to put the outcome beyond doubt, the England captain accruing 6 fours.