Samit Patel's quick-fire 45 proved crucial as Notts Outlaws reached the NatWest T20 Blast Finals Day with a five-wicket win over Somerset, at Trent Bridge.
Patel's 28-ball knock, coupled to a late Dan Christian salvo of 36 not out off 26 balls, steered the Outlaws to their victory target in 18.3 overs after Somerset gamely tried to defend 151-6.
Christian's side join Hampshire and Glamorgan in the last four, while Surrey and Birmingham Bears will contest the final quarter-final live on Sky Sports Cricket on Friday.
Somerset struggled to set an imposing target despite an 85-run stand between Steven Davies (59 off 41) and Peter Trego (40) - twice losing two wickets in as many balls.
Jake Ball (2-21) bagged a double-wicket maiden in the third over of the match, bowling stand-in skipper Lewis Gregory before Johann Myburgh snicked his first ball behind.
Trego survived the hat-trick ball and struck a couple of sixes while Davies caressed the ball through the off-side on his way to a 33-ball fifty.
The partnership was ready to kick on when Ball pulled off a fine diving catch at deep square to remove Trego before James Hildreth got the second golden duck of the innings, leading edge back to Samit Patel (2-26) as he looked to turn leg.
Roelof van der Merwe played out the hat-trick ball for one, going on to accumulate 27no off 18 balls, but only four boundaries came in the last eight overs as Nottinghamshire turned the screw.
The home fans, buoyant at the break, were silenced shortly into the reply though when Riki Wessels pulled a dragged-down delivery from Max Waller to Craig Overton in the deep.
Alex Hales (14) steadied the ship with three consecutive fours off Craig Overton only to fall to a fine low catch by Trego at mid-off - the officials ruling the ball had just carried - and Tom Moores' brisk 13 ended when he was caught on the rope by van der Merwe, making it 34-3.
Notts were four down at the half-way stage still needing 83 after Brendan Taylor (20 off 20) was run out by Myburgh attempting the tightest of singles.
Patel and Christian struck 20 off five balls between them to get the run-rate below eight and then helped a slower ball from Paul van Meekeren over deep square for his second maximum.
With 32 needed from 30 balls, Gregory kicked the ball onto the stumps at the striker's end as Patel failed in vain to sneak a quick single.
The telling over proved to be the 18th - Christian and Steven Mullaney each scoring a six off Craig Overton as it went for 19.
Mullaney finished the match by swatting Gregory for four to send Nottinghamshire Outlaws through to Finals Day for the fourth time.
Watch the fourth and final NatWest T20 Blast quarter-final between Surrey and Birmingham Bears live on Sky Sports Cricket from 6.45pm on Friday.