Cameron White's destructive half-century saw Northants Steelbacks to Friends Life t20 Finals Day for only the second time as they beat Durham Dynamos by 36 runs at Wantage Road.
A strong showing of 183 for four with the bat proved decisive, led by an explosive 32-ball 58 from the Australian all-rounder, before the hosts produced a superbly polished performance in the field.
Durham Ben Stokes fired a similarly impressive unbeaten 51 off 29 deliveries but his efforts came too little, too late.
Having won the toss and elected to have bat first, the Steelbacks made steady progress in the initial stages.
David Willey, promoted to open, joined Kyle Coetzer and the pair made efficient use of the six-over powerplay, which ended at 40 without loss.
It was not spectacular, as a controlled spell from England seamer Graham Onions ensured the shackles never truly came off, but enough impetus was created for the required acceleration.
That came primarily from Willey, who blazed his way to a 34-ball 46 before a swipe across the line saw him bowled by Gareth Breese.
Kyle Coetzer fell for 44 shortly after Northants brought up three figures when a smart piece of work from Phil Mustard caught him short of his ground, setting the stage for White.
A a trio of sixes in one Breese over - the 16th – provided the glorious centrepiece to an innings that ultimately took the game beyond Durham’s reach.
White motored to his 50 from 27 balls and, as Alex Wakely provided good support with 20 from 14 deliveries, 79 runs came from the last six overs.
The reply didn't start too promisingly for the Dynamos as both Mustard and Mark Stoneman struggled to get going and it was no surprise when the latter lost his middle stump to Steven Crook.
Already behind the rate, the visitors could not find the boundary with any regularity and at the halfway point a further 131 runs were needed.
Durham’s chances looked to have departed when Mustard fell for 46, top-edging a sweep off James Middlebrook, but Stokes kept them flickering with a brutal display.
The big-hitting all-rounder landed a handful of meaty blows – three fours and four sixes - in a rapid half-century, but it was to no avail as Durham fell comfortably short on 147 for six.
Seamer Lee Daggart typified Northants’ exploits with the ball as he finished with magnificent economical figures of 1-13 from his four over allocation.