Pete Trego and Arul Suppiah set Somerset on the path to their third win from three games in the Yorkshire Bank 40 as they overcame Middlesex by six wickets with 25 balls to spare at Taunton.
Middlesex were restricted to 252 for nine after they had lost the toss, with seamer Steve Kirby claiming four wickets and leg spinner Max Waller chipping in with three scalps.
But despite going at more than a run a ball, it proved a below par total as Trego and Suppiah bludgeoned 81 and 60 respectively before James Hildreth and Jos Buttler saw the hosts over the line.
After being put into bat Middlesex openers Chris Rogers and Dawid Malan looked untroubled as they took the total onto 73 before Craig Meschede entered the attack and had Rogers, on 29, well caught at deep midwicket by Alviro Petersen.
Malan looked comfortable but was on 49 when he pulled Max Waller to James Hildreth at short midwicket. The leg spinner struck again soon after by firing in a quicker ball which Paul Stirling drove straight back to the bowler.
Waller changed ends and claimed his third victim when Adam Rossington tried to clear the midwicket ropes and was caught by Lewis Gregory for 12.
With the total on 139 for four Neil Dexter and Joe Denly came together and took the total onto 222 before Gregory had Dexter (37) leg before wicket trying to work the ball to fine leg. The fifth wicket partnership added 83 in just over 12 overs.
In the penultimate over Kirby claimed three wickets in four balls as the visitors ended on 252 for nine.
Somerset openers Marcus Trescothick and Trego started briskly and it was latter who brought up the 50 with two to backward square-leg off James Harris in the seventh over.
Gareth Berg broke the partnership at the start of the eighth over after being introduced into the attack when he had Trescothick, looking to steer the ball to fine leg, caught behind
Trego was joined by Suppiah and it was the former who brought up the 100 with a single to mid-off in the 14th over. A single into midwicket off Tim Murtagh's next over saw Trego to 50 off 46 balls.
Suppiah showed his best form of the season with the bat and went to his half-century with a lofted straight drive off Malan. When Tom Smith returned to the attack, Trego hoisted his first ball over midwicket but two deliveries later was caught by Rogers at long-on for 81. The second wicket partnership between Trego and Suppiah yielded 110 runs in 14.3 overs.
Suppiah had moved onto 60 when he top edged Harris into the air to Rossington with the total on 173.
Hildreth (37 not out) made his intentions known straight from the off when he pulled Harris to the midwicket boundary and then proceeded to take 18 off Corey Collymore's fourth over.
At the opposite end Petersen had been subdued until he drove Smith high over long-on for six. The South African Test batsman had moved onto 17 when he was caught at long-off by Smith off Murtagh.
Buttler (27 no) came to the crease with 30 still needed but the England limited-overs batsman showed typical panache and finished the job in style with a six over midwicket with the penultimate ball of the 36th over.
Adam Lyth's unbeaten half-century carried Yorkshire to a first win of the season in the competition, at the expense of the Unicorns at Chesterfield.
The Unicorns made 189 for nine after choosing to bat first – number nine Aneurin Norman top-scoring with 38 from 26 balls and Richard Pyrah claiming three wickets.
Gary Ballance's 44 made inroads into the total and Lyth, with 58no from 60 balls, reeled in the target with seven balls left.
Group B leaders Hampshire recorded a third win from four matches as Michael Carberry's 96 saw them to a five-wicket success over Durham.
