Half-centuries from Heather Knight and Dani Gibson helped Somerset beat Lancashire by four wickets at Southport.
Lancashire had set a competitive target thanks to half-centuries of their own from skipper Ellie Threlkeld (71) and Fi Morris (52) but despite three wickets from England spinner Sophie Ecclestone, the visitors reached the winning total with 13 balls remaining.
Lancashire, who were put into bat, lost opener Emma Lamb to injury late on and her replacement, Alice Clarke, became the first batter out when she was dismissed for six in the third over, caught behind off Alex Griffiths.
Eve Jones and Seren Smale were progressing nicely until Smale fell victim to a brilliant piece of wicketkeeping from Jess Hazell and was out stumped off Charlie Dean for 18.
Jones (38) was next to go caught at long-on off a full toss from Lola Harris and with Lancashire 90-3 a partnership was needed.
Threlkeld and Morris obliged, with the captain especially fluent as she targeted the spinners and moved to her half-century as the pair put on 88 for the fourth wicket.
Threlkeld eventually fell for 71, bowled by Harris but Morris kept going and brought up her own half-century only to get out the very next ball caught by Gibson off Griffiths.
The hosts had a platform to accelerate and Ailsa Lister (20) and Kate Cross (21) supplied quick runs before Griffiths took the last two wickets to fall as she finished with 3-51.
Somerset set about the target in serene fashion and it took a brilliant catch from Morris at mid-wicket to dismiss opener Bex Odgers for 17 off Mahika Gaur.
Ecclestone entered the fray early to bowl against her former England captain Knight but it was Niamh Holland who became her first victim when she was bowled for 25.
When Somerset skipper Sophie Luff fell for 10, well caught by a tumbling Cross off Darcey Carter, Lancashire looked to be edging the contest with the visitors 132-4.
But that did not account for Knight, who together with Gibson, began to compile the partnership that sealed the match.
The duo had put on 53 when Knight was trapped in front by Ecclestone for 63 but Gibson took over as she tackled the run rate with ease thanks to some powerful hitting, including two sixes and eight fours in her innings of 60.
Ecclestone eventually accounted for Gibson, bowled attempting a sweep, but the damage was done and Dean (21 not out) and Hazell (21 not out) saw Somerset home in the 48th over.