Essex 170 for 6 (ten Doeschate 56) beat Somerset 148 for 9 (Water 3-28, Harmer 3-39) by 22 runs
South African spin bowler Simon Harmer led a parsimonious attack in defending a total of 170 to give Essex their first win of the NatWest T20 Blast campaign.
Harmer, who has taken the red-ball domestic cricket by storm with 47 Specsavers County Championship wickets to date, added three more white-ball victims to his tally as his 3 for 39 from four overs ended Essex's two-defeat start to the campaign.
Harmer was backed up by a fine spell by Pakistan paceman Mohammad Amir, who posted outstanding figures of 1 for 17 from his 24 balls. Paul Walter took two wickets in the final over to finish with 3 for 28.
Somerset were undone by two wickets in five balls by Harmer mid-innings and were unable to keep up with the required run rate, falling short by 22 runs.
Essex had struggled to penetrate some outstanding Somerset fielding and were indebted to Ryan ten Doeschate's 37-ball 56 and some lusty late hitting by Ashar Zaidi, who included three sixes in his 35, for setting what turned out to be a matchwinning total.
Chasing 171, Somerset lost Johann Myburgh to a top-edge that lobbed to Harmer at backward point to give Jamie Porter his first T20 wicket.
Two wickets in the eighth over for Harmer knocked the stuffing out of Somerset's reply after they had reached 47 for 1. He had Jim Allenby caught in the covers by ten Doeschate and Peter Trego pouched on the long-off boundary by Tom Westley.
Steven Davies was next to go when he swished at a wide one down legside from Ravi Bopara and was caught behind. Suddenly Somerset were 58 for 4 and nine overs gone.
Like Essex, Somerset were struggling to get the ball away on a slow pitch, but Adam Hose and James Hildreth tried the aerial route with straight sixes off Zaidi and Bopara respectively. But when Hildreth attempted to do the same to Harmer he was caught by ten Doeschate diving forward on the long-leg boundary for 27.
Hose got a bottom edge to Amir to give James Foster his second catch behind and Lewis Gregory was caught behind for a belligerent 23 off 12 balls. But time and overs were running out for Somerset. They required 36 from 12 balls with Amir restricting them to just eight from the penultimate over.
Craig Overton went for broke but was caught at cow corner by Dan Lawrence before Tim Groenewald was held by Zaidi to give Walter two wickets in the final over.
Essex had looked in some trouble themselves from the start of their innings and were 36 for 3 in the sixth over after being put in.
Lawrence started the rot when he lost his off-stump going for an ungainly heave against Gregory. He was followed swiftly by Varun Chopra who was reprieved by Hose's dropped catch at deep mid-on, but next ball skied Craig Overton and Groenewald took the catch at short third man. And Westley departed when he played over a slower delivery from Groenewald.
Bopara and ten Doeschate set about a repair job, turning singles into twos, with the captain upping the tempo with a straight six and a one-bounce four off successive balls from Roelof van der Merwe.
But when the partnership had reached 50 inside six overs, Max Waller took a brilliant return catch low to his left to remove Bopara for 24.
Essex became bogged down in the middle overs before Zaidi pulled Waller for successive sixes over the short midwicket boundary and out of the ground.
Ten Doeschate hooked Overton for four before pushing a two into the on-side to reach fifty off 34 balls that included five fours and a six. But he departed in the penultimate over, caught on the long-off boundary by Overton diving forward.
Zaidi launched his third six over midwicket in the same over, but was caught out of his ground for 35 when James Foster hit the ball straight back to van der Merwe who turned and removed the bails. But Essex's total proved to be enough.