Somerset 154 for 6 (Banton 54, Douthwaite 3-26) beat Glamorgan 153 (Byrom 42, van der Merwe 3-24) by four wickets

Banton dominated an opening stand of 69 with Will Smeed and went on to make 54 from 28 balls, his highest score of the campaign, to help propel the cider county to victory with 5.1 overs to spare in front of a near full-house crowd.

Now top of the table following Surrey's defeat at the hands of Sussex, Somerset remain the only side in the South Group to boast a 100% record, while Glamorgan have won one and lost one under new head coach Mark Alleyne.

Put into bat on a good pitch, Glamorgan made a decent start thanks to Byrom and Carlson, who staged an aggressive half-century stand in 5.5 overs. Perhaps with a point to prove against his former county, Byrom adopted a long-handle approach, hitting Matt Henry for a six and two fours in three successive balls in the second over. He then deposited Siddle over midwicket for another towering six as the Welsh side achieved lift-off.

Overton served up a wicket maiden to remove Sam Northeast for 2, held by Tom Lammonby at third man, but Carlson looked the part as he claimed a brace of sixes off the same bowler, one a scoop over fine leg, the other a more orthodox affair high over long-on.

Glamorgan were 57 for 1 at the end of the six-over powerplay, but came under pressure as spinner van der Merwe and seamer Ben Green turned off the hitherto ready supply of boundaries. Attempting to sweep van der Merwe, Byrom missed and was trapped lbw, having scored five fours and two sixes. Gregory then struck with his first delivery, Carlson caught in the deep by Tom Abell.

Taking full advantage of their double breakthrough, Somerset applied the squeeze, Gregory persuading the dangerous Colin Ingram to hit to deep midwicket for 13 and van der Merwe having Ben Kellaway held at long-on as Glamorgan slipped to 100 for 5 in the 13th over.

Chris Cooke carved 18 runs from 16 balls to threaten a Welsh revival, only to fall to the returning Henry, who had him caught at long-on. When Dan Douthwaite was dismissed in identical fashion off the bowling of van der Merwe, the visitors were 129 for 7 in the 17th over and in danger of falling short.

Billy Root made 18 from 16 balls but perished at the hands of Siddle, while Ruaidhri Smith skied a catch to extra cover off the bowling of Green. New overseas recruit Peter Hatzoglou smashed 15 off eight balls before hoisting Siddle to Overton at long-on as the visitors were dismissed with two balls unused.

Banton afforded Somerset's chase a super-charged start, plundering three fours and a six from successive balls in an over from Australian leg spinner Hatzoglou that went for 23 runs. Not to be upstaged, Smeed drove down the ground with increasing fluency as the openers raised 50 in 3.5 overs to seize the initiative.

Having contributed his highest score of the campaign and played his part in a whirlwind opening stand of 69 in 5.5 overs, Smeed drove Douthwaite straight to mid-off, departing for a 14-ball 28. By the end of the powerplay, Somerset were 72 for 1 and the required rate was down to 5.9.

Nevertheless, Tom Kohler-Cadmore was in no mood to hang about and the former Yorkshire man smashed Smith for consecutive sixes over long-on and midwicket before chancing his arm once too often and holing out to backward point for 19 later in the same over.

There was no stopping Banton, however, the right-hander going to his first Blast fifty of the season via 26 balls. Having set-up a successful chase, he was unable to finish the job, hitting Douthwaite to mid-off in the tenth over, by which time he had amassed nine fours and a six and Somerset were 116 for 3, requiring a further 38 runs at just under four an over.

Lammonby came and went quickly, but Abell and Gregory eschewed unnecessary risk in a fifth-wicket partnership of 25, which took the home side to the brink of victory. Abell was bowled for a 17-ball 22 and Gregory went for 11, leaving Green to strike the winning runs.