Glamorgan 176 for 7 (Douthwaite 56*, Ingram 55, Henry 2-15) beat Somerset 174 for 9 (Smeed 72, Leonard 5-25) by two runs
Ned Leonard claimed five wickets against his former county as Glamorgan shocked South Group leaders Somerset with a nail-biting two-run Vitality Blast win at Taunton.
The visitors posted 176 for six after losing the toss, Dan Douthwaite top-scoring with 56 off 32 balls, with three fours and four sixes, while Colin Ingram hit 55 from 33 deliveries. Matt Henry finished with two for 15 from four overs.
In reply, Somerset fell just short on 174 for nine, Will Smeed making 72 off 49 balls and Leonard claiming five for 25. It was only Glamorgan's fifth victory in 20 Blast visits to Taunton.
Henry's first two overs of the match saw Will Smale caught by Craig Overton over his shoulder at mid-on and Alex Horton top-edge a pull shot to Meredith at fine leg to make it 22 for two.
Ben Kellaway hit successive boundaries off Overton in the fifth over and the end of the power play saw Glamorgan 42 for two. That became 66 for three when left-arm spinner Lewis Goldsworthy had Kiran Carlson, on 14, brilliantly caught by the diving Tom Abell at deep mid-wicket.
When Kellaway, who had moved to 28, top-edged an attempted reverse sweep off Goldsworthy to Tom Kohler-Cadmore at short third-man, Glamorgan were struggling on 75 for four in the 11th over.
It was 94 for five when Riley Meredith dismissed Asa Tribe, caught behind cutting, but the Australian's next over saw Douthwaite, on two, dropped by wicketkeeper Tom Banton and it proved a costly error.
Ingram moved to a powerful 31-ball half-century with a six off Meredith. Ben Green struck a big blow for Somerset when having the South African caught at short third-man off a top edge with the total on 143 in the 18th over.
Douthwaite smacked Lewis Gregory for 4,4,6 at the start of the 19th over and another six took him to fifty off 29 balls. He was run out off the final delivery of the innings, having cleared the ropes again off Meredith.
Somerset had reached 25 off 3.5 overs when Banton was caught at mid-off miscuing a delivery from Leonard, who followed up by bowling Kohler-Cadmore behind his legs.
The hosts had posted 41 for two at the end of the power play and were in some bother when Tom Abell fell for a duck, superbly caught by Douthwaite off his own bowling to make it 44 for three. Sean Dickson and Smeed lifted the tempo with sixes off Kellaway and at the halfway point in their innings Somerset were 77 for three, needing exactly 100.
Dickson had made 27 off 17 balls when top-edging a slog sweep off Andy Gorvin to make it 97 for four after 12 overs. Smeed moved to a 35-ball fifty, but Gregory fell quickly to Leonard and at 100 for five the home side were in a deepening hole.
The target became 55 off five overs and then 35 off three as Green and Smeed produced some clean hitting against tight Glamorgan bowling. Green hit a straight six of Jamie McIlroy, who quickly responded by having Smeed caught at wide long-off.
Leonard then had Green caught off a skyer and Craig Overton taken at deep mid-wicket to complete his five-for and 16 off the final over, bowled by Douthwaite, proved just too many for Somerset.
