On a sweltering evening, the hosts recovered from a slow start to run up 184 for six, and Gloucestershire fell just seven runs short in the chase
Taunton: Somerset 184-6, Gloucestershire 177-8 - Somerset won by seven runs
Rapid half-centuries from Rilee Rossouw and Lewis Gregory paved the way for Somerset to clinch a Vitality Blast double over arch-rivals Gloucestershire with a seven-run win at a packed Cooper Associates County Ground.
On a sweltering evening, the hosts recovered from a slow start to run up 184 for six, Rossouw smacking 54 off 45 balls, with three sixes and five fours, while Gregory hammered 60 from 36 deliveries, clearing the ropes five times.
Mohammad Amir (2-25) and Benny Howell (2-31) were the pick of bowlers for Gloucestershire, who made a promising start in reply, but were eventually restricted to 177 for 8.
Ryan Higgins hit 43 and Benny Howell 42, but the visitors lost their way in the middle of the innings. Peter Siddle claimed 3 for 30 and Roelof van der Merwe 1 for 31.
All the talk before the game was about 200 being a par score on a good-looking pitch. But it gripped slightly to give the bowlers on both sides hope.
Somerset soon found that to their cost as Will Smeed swung at the first two deliveries of the game from Amir without making contact and edged the third to slip.
Tom Abell and Lewis Gregory celebrate a wicket during Somerset's win over Gloucestershire [Harry Trump/Getty Images]
The Pakistan left-arm seamer went on to complete a wicket maiden and, far from making a fast start, the home side were becalmed on 4 for 1 at the end of the third over.
Tom Banton and Rossouw than upped the pace, only for Banton to fall for 23 in the sixth over, bowled by Glenn Phillips, which ended with Somerset 43 for 2.
Tom Abell offered a tame caught and bowled to Howell, who bowled with typically clever variation of pace, line and length.
Tom Lammonby fell to an ugly shot off Zak Chappell and at the halfway point of their innings his side had posted only 69 for 4.
Rossouw cut loose with two sixes and a four off Ryan Higgins in going to a 33-ball fifty. But when he fell to Howell in the 13th over, Somerset needed a hero.
They found one in Gregory, fresh from a confidence-boosting LV= Insurance County Championship century against Surrey. The allrounder cleared the ropes off Tom Smith, Chappell, Howell and Matt Taylor, whose 19th over cost 23, to boost what was looking a below-par score.
The highlight of Gloucestershire's fielding was stunning one-handed boundary catch by Miles Hammond to dismiss Ben Green.
Hammond soon signalled his side's intentions with the bat, hoisting the first ball of their reply from Siddle over midwicket for six.
Somerset appeared to have learned little about the left-handed opener's relish for scoring in that area from the reverse fixture eight day earlier and soon he was finding it again for another maximum off Gregory.
Rilee Rossouw completes a fine catch on the boundary [Harry Trump/Getty Images]
Ultimately, it proved Hammond's downfall as, on 19, he miscued a catch to wicketkeeper Banton off Jack Brooks. But by then Gloucestershire had raced to 33 off 3.1 overs.
At the end of the six-over powerplay, the visitors had 51 for 1 on the board and looked well placed.
But Somerset then applied the sort of mid-innings squeeze their opponents have been so effective at over the years, spinners van der Merwe and Goldsworthy sharing six overs for just 42 runs.
James Bracey (30), Glenn Phillips, Ian Cockbain and Jack Taylor all fell between the eighth and 13th over, the last of them to a one-handed boundary catch by Rossouw at long-on that rivalled Hammond's.
Higgins and Howell briefly raised Gloucestershire hopes, the latter hitting sixes off successive balls from Green, before Siddle's experience saw him effectively close out the match by taking three wickets in the 19th over.
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