A brutal half century from Marcus Trescothick helped Somerset set up a Twenty20 final against Sussex after a comfortable seven-wicket win over Kent.
The opener smashed 56 from just 32 deliveries while James Hildreth's assured 36 saw the 2005 champions overhaul Kent's total of 145-5.
Darren Stevens's 77 was the highlight of Kent's innings, and he was joined in a stand of 61 by captain Rob Key (34).
Seamer Alfonso Thomas (2-26) was Somerset's outstanding bowler.
Presented with a placid pitch which had restricted the Northants batsmen in the first semi-final of the day, Somerset captain Justin Langer won the toss and elected to field.
His decision immediately paid dividends when Thomas uprooted Joe Denly's middle stump before trapping the dangerous Martin van Jaarsveld lbw for 10.
Charl Willboughy soon bowled Geraint Jones as Kent stuttered to 32-3 after the six-over powerplay but a spirited fourth-wicket partnership between Key and Stevens steadied the innings as Somerset pushed for further openings.
Key was eventually bowled by Peter Trego, albeit in bizarre circumstances when the ball clipped off stump before ricocheting off wicketkeeper Craig Kieswetter's pads on to the stumps.
Umpires Ian Gould and Rob Bailey consulted television official Richard Illingworth, who confirmed the ball had dislodged the bail before cannoning off the wicketkeeper's pads, much to Key's annoyance.
However, two generous overs from spinners Max Waller and Arul Suppiah - whose final six deliveries cost 20 runs - pushed Kent to 145-5, with Stevens run out off the final ball of the innings for a career-best score from 51 deliveries, including seven boundaries and two sixes.