Somerset 155-4 (Petersen 64*, Trego 41, Willey 2-19) beat Northamptonshire 152-7 (Willey 47, Thomas 3-33) by three runs
Alviro Petersen hit a match-winning half-century as Somerset made it maximum points from their first two Friends Life t20 games with a six-wicket victory over Northamptonshire at Taunton.
The hosts reached a target of 153 with seven balls to spare with Petersen finishing unbeaten on 64 off 35 balls having struck seven fours and two sixes.
Peter Trego contributed 41 for the victors, while David Willey was the pick of the Northamptonshire attack with two for 19 from four overs.
Willey was also the mainstay of his side's batting after they had won the toss in glorious sunshine. He made 47, but the visitors found it difficult to gain momentum as Alfonso Thomas claimed 3 for 33.
Yasir Arafat had set the tone for a tight Somerset bowling effort by making the first over of the Northants innings a maiden to Richard Levi. By the end of the six powerplay overs the visitors were 29 for one as Steve Kirby and Thomas maintained a grip.
Former Somerset player Cameron White and skipper Alex Wakely both carelessly gifted catches to cover and it was left to Willey, who announced his intentions by pulling his first ball for Kirby over mid-wicket for six, to bolster the Northamptonshire total. He faced only 29 balls, hitting four fours and two sixes, but lacked support.
Northamptonshire's total looked 30 below par in such ideal batting conditions and Somerset paced their reply perfectly, despite losing skipper Marcus Trescothick for his second duck in as many games, caught at slip off a Willey lifter.
It was 50 for two when Craig Kieswetter was caught at long-on to give Willey another wicket, but Trego and Petersen then added 40 in less than five overs while taking few risks.
Trego was never at his most fluent and eventually fell lbw to the left-arm spin of Graeme White, having faced 42 balls and hit four boundaries and a six.
Petersen scored off virtually every ball he faced and accelerated just when the situation demanded. Jos Buttler helped supply the finishing touch after James Hildreth had been run out.