Durham have been defeated in their quarter final at Northampton by 36 runs, outclassed by a big hitting Steelbacks side.
After winning the toss and electing to bat the Steelbacks got off to a good start and were 40-0 after the first six overs and at the end of the power play.
Despite no wickets tumbling, the Durham bowlers had a reasonable start too with the Northants finding the just six times in the opening six overs.
Northants then found some rhythm with the bat and amped up their run rate to be 85-0 after 11 overs, Durham still hunting for the first wicket.
However just after the half way mark, Gareth Breese got the breakthrough in the 12th over when he bowled Willey for 46 from 34 with a superb delivery.
The following over saw some sensational work by wicketkeeper Mustard who scrambled and spun and threw to the other end with a direct hit to dismiss Coetzer for 44 leaving Northants 102-2.
The Durham bowlers continued to somewhat tame the Steelbacks until Cameron White took a fancy to Breese in the 15th over, smashing three big sixes from the one over and increasing the home sides run rate.
White continued to be the destroyer in the home-sides innings as he found the boundaries with ease surpassing his 50 off just 27 balls.
With three balls to go Durham got their third wicket when Wakely hit one straight up to find the hands of Collingwood and the next ball Collingwood was again amongst the wickets, running out Crook as he came back for a second.
Northants finished their innings on 183-4 with Cameron White 58no from just 32 balls to give the home-side a big total
Chasing just over 9 an over the Dynamos got off to a reasonable start through Stoneman and Mustard until Stoneman was bowled the last ball of the 5th over for 20 with the scorecard reading 28-1.
Scott Borthwick made just the four before he top edged high to depart in the 8th over leaving Durham 39-2.
Phil Mustard continued at the crease and at the half way mark the Dynamos were facing an uphill battle needing 130 from 60 balls sitting at 54-2.
With two big hitters at the crease however anything was possible as Mustard and Muchall did their best to eat away at the target adding 34 runs together.
Mustard registered the first six of the innings and then fell short with a sweep the next ball to depart in the 12th over for 46 from 34 balls with Middlebrook the wicket.
Ben Stokes and Gordon Muchall then tried their very best to chase the required runs down with Stokes yet again impressive with his big shot making with some huge sixes.
The pair put on a 65 run partnership but the run rate was just too much for the Dynamos and when Muchall chipped and found the Northants fielder with 2 overs to go Durham required 46 off the final two overs.
Stokes surpassed 50 with 10 balls to go with his half century coming off just 25 balls and including 7 boundaries.
Gareth Breese was sent in before Collingwood with the skipper hoping for some big shots but Breese was bowled for just 1 with just over an over to go and Pringle the next man in was dismissed with just the 1 ball to go.
Stokes finished on 51 no (from 29 balls) as Durham fell 36 runs short, denied a Finals Day appearance by a stronger Northants side.
Despite the loss the side can say the t20 season was a positive one with some impressive performances from both the experienced players alongside the youngsters including Stokes, Borthwick and Pringle throughout the competition.