Worcestershire 191 for 5 (Russell 77*) beat Somerset 188 for 4 (Kieswetter 80, Trego 62) by five wickets
A whirlwind half-century by West Indian Andre Russell delayed Somerset's march towards the Friends Life t20 quarter-finals as Worcestershire registered a surprise five-wicket win at New Road.
Worcestershire ended a run of three defeats and climbed off the bottom of the Midlands/Wales/West group by overhauling Somerset's formidable total of 188 for 4 with two balls to spare.
Russell led the charge to victory with six sixes in an unbeaten 77 from 42 balls - his highest score on a T20 contract for the county - and Ross Whiteley, newly signed from Derbyshire, was the perfect foil with 43 on his debut.
The tall left hander cleared the rope twice in stand of 88 in nine overs before a top edge off Yasir Arafat was well taken by Chris Jones at deep midwicket.
The momentum was then so much with Worcestershire that two fours by Russell in the last over from Craig Meschede completed a double over Somerset in the group.
Worcestershire lost early wickets but with rain threatening they made brisk progress through Alexei Kervezee, with 32 on stepping up to open, and Daryl Mitchell with 23 until he was leg-before to George Dockrell's first ball.
Somerset had made a bad start when Jones popped up a return chance to Jack Shantry but Worcestershire subsequently conceded eight sixes and 14 fours on a good batting surface.
Peter Trego led the way with 62 from only 31 balls and Craig Kieswetter was close to batting through the innings, cruising to 80 from 56 deliveries, before he was caught at wide long on in the 19th over. The pressure exerted by two batsmen targeting the shorter boundaries led to a number of fielding errors as Somerset romped to 61 in the six-over power play.
Trego was the chief enforcer, bludgeoning three sixes and eight fours until Worcestershire captain Mitchell appeared as the sixth bowler and beat the allrounder's attempt to drive his fourth delivery.
Jos Buttler briefly showed his flair for the shorter format until he was also bowled, making a complete mess of the scoop shot, but Kieswetter continued on his trouble-free course. Selective hitting brought four sixes and five fours before falling to Shantry with a neat catch by Whiteley.