Nottinghamshire reached the Yorkshire Bank 40 final with an eight-wicket thrashing of Somerset at Trent Bridge.
In a match reduced to 35 overs per side by rain, Somerset were bowled out for 119 after being sent in.
Nottinghamshire seamer Jake Ball claimed one-day best figures of 4-25 and Steven Mullaney 3-35, while Peter Trego's 40 was the top score of an innings lasting 25.4 overs.
Steve Kirby trapped Alex Hales lbw for five in the second over of Nottinghamshire's run chase but a 38-ball 46 from Michael Lumb put the home side on course.
James Taylor and Samit Patel shared a third-wicket stand of 60 to finish the match with 18 overs to spare.
Nottinghamshire's reward is a Lord's showdown against Glamorgan on September 21, their first domestic one-day final since 1989.
Left-arm seamer Harry Gurney (1-11) set the tone in the first over of the game by having Somerset skipper Marcus Trescothick caught behind for a duck.
No.3 Trego forged promising stands of 37 and 25 with Craig Kieswetter (22) and Nick Compton (14).
But Nottinghamshire ended both partnerships just as they started to flourish. Ajmal Shahzad (2-23) accounted for Kieswetter via a toe-ended pull and Mullaney had Compton caught by David Hussey running back from cover.
From 62-2, Somerset's last eight wickets went down in 14.5 overs, including a return catch from Trego to Mullaney.
Ball ran through the lower order in quick time, winning lbw verdicts against Alfonso Thomas (1) and Jamie Overton (0) with successive deliveries.
Hales' early departure was a mere blip for Nottinghamshire's run chase as his opening partner Lumb hammered 10 fours.
Overton (1-35), the 19-year-old fast bowler released from England's one-day squad to play in this match, denied Lumb a half-century by having him caught behind.
But Patel slammed eight fours in his 26-ball 43 not out to see Nottinghamshire home in the 17th over alongside Taylor (20no).