Rossington's 67* gives Northants win
Middlesex post 132-7 (20 overs)
Bailey top scores with 46 for visitors
Notts beat Essex in first quarter-final
T20 Blast Finals Day on 20 August
Northants 27-1 (4 overs) v Middlesex 132-7
But, not to be deterred by the loss of Richard Levi, Adam Rossington has crashed Harry Podmore for six to race the hosts towards 27-1 off four overs.
Middlesex don't have many runs to play with, and regular wickets are an absolute must.
Not too shabby an over that, from Toby Roland-Jones. Just checking the progress of Northants, who now have Josh Cobb at the crease.
Northants 18-1 (2.4 overs) v Middlesex 132-7
But Richard Levi, trying to repeat his trick of the previous over, is perhaps just beaten for pace by Toby Roland-Jones and can only spoon a catch to James Franklin at fine leg. Boy, did Middlesex need that.
Northants 12-0 (2 overs) v Middlesex 132-7
Image source, Getty ImagesTake that!
Richard Levi, very much the stand-and-deliver-type batsman, launches poor old Harry Podmore down to his favourite cow corner and out of the ground. Huge.
Twelve from the first 12 balls.
Toby Roland-Jones sends down a lively first over, beating the outside of Richard Levi's bat with his fifth delivery, but there's no reward for the Middlesex seamer and a handful of singles helps Northants to a steady start.
Adam Rossington and Richard Levi are in the middle, Toby Roland-Jones has the ball in his hand, and so I think the Northants reply is about ready to begin.
Let's get cracking...
And that's your lot. James Franklin ends unbeaten on 21, his partner Ollie Rayner on two.
I reckon Northants will be very happy with their 20 overs' work, but it's still all to play for. I'll be back with you in around 10 minutes.
Six balls to go, what can Middlesex muster up?
Ollie Rayner joins James Franklin, who has 15 from 12 deliveries. Azharullah to bowl.
Middlesex 120-7 (18.4 overs) v Northants
Image source, Getty ImagesAnd, after a rather hopeless attempted switch hit brings about another dot, Ryan Higgins is finally put out of his misery.
He launches Rory Kleinveldt straight up, and then straight back down into the South African's big, welcoming hands.
This is really fine bowling from Richard Glesson, who, recognising Ryan Higgins is determined to give himself room to hit through the covers, continually bangs it in short at varying pace.
Five from the over, 12 balls to come.
I think you'd take that from the 17th over of an innings every time - one run from it, and the wicket of Toby Roland-Jones.
Middlesex have 18 balls to save their T20 Blast campaign.
Middlesex 111-6 (16.2 overs) v Northants
And the away side are quickly running out of recognised batsman too, as Toby Roland-Jones hammers a short ball from Rory Kleinveldt high into the dusk sky and down into the grateful hands of Josh Cobb.
Northants well and truly on top.
Toby Roland-Jones and James Franklin have some rebuilding job to do here, both relatively new to the crease and with their Middlesex side looking short of a competitive total.
Seven from that last over - but most crucially the key wicket.
James Taylor
Ex-England batsman on BBC Radio 5 live sports extra
Quote MessageThat's a huge wicket. It's a massively valuable innings from George Bailey, but again it's a timely wicket for Northants - every time they look like they've got something going Middlesex lose a wicket.
Middlesex 104-5 (15.1 overs) v Northants
Image source, Getty ImagesThe big one!
George Bailey, just four short of a half-century, tries to hammer the returning Richard Gleeson to the boundary but can only pick out Richard Levi on the edge of the circle.
That's the wicket Northants will have been desperate to take.
Middlesex 104-4 (15 overs) v Northants
Ben Duckett, who so brilliantly caught John Simpson just a moment ago, has had a shocker here.
George Bailey comes skipping down the track to Graeme White, launches a huge heave-ho into the leg side... But Duckett, who lines it up nicely, spills it over the boundary rope. That was all or nothing for Bailey, who is now 46 not out.
Well bowled, Seekkuge Prasanna. The spinner's four overs have gone for just 20 runs and seen off both Paul Stirling and John Simpson.
Six overs to go, fireworks needed.
Middlesex 93-4 (13.4 overs) v Northants
Another one bites the dust!
John Simpson is the latest to go, again caught on the rope down at long on - and a fine grab it is too, Ben Duckett, only a few inches in from the boundary, takes it above his head.
James Franklin's next up.
But while George Bailey's there - as he is, still unbeaten on 36 from 39 balls - this could yet get messy.
Nine runs come from that latest Graeme White over.
Another fine over from Seekkuge Prasanna, whose three sets have gone for only 11, as well as snaffling the crucial wicket of Paul Stirling.
John Simpson is the new man in.