Worcestershire Rapids skipper Daryl Mitchell produced a stunning performance with the ball as his side overpowered Northamptonshire Steelbacks by 31 runs to take a big step towards the quarter-finals of the NatWest T20 Blast.

Victory over Derbyshire Falcons at New Road next Friday will guarantee a last eight spot for the Rapids irrespective of what happens elsewhere.

Mitchell has starred with the bat this so often season in all forms of cricket but it was his medium pacers which destroyed holders Northants under their own floodlights with 5-28 from his four overs.

There was also a superb contribution from Shaaiq Choudhry (2-21) who took over from Saeed Ajmal in the spinning role as the home side were dismissed for 131 in the 19th over.

The Rapids are now back into second spot in the table with 16 points after Yorkshire Vikings defeat against Birmingham Bears this evening.

Worcestershire reached 162-9 after electing to bat thanks mainly to contributions from Colin Munro and wicket-keeper Ben Cox.

The Rapids gave a debut to New Zealand paceman Mitchell McClenaghan in place of Ajmal and made two other changes with Joe Leach and Choudhry replacing Alexei Kervezee and Chris Russell.

Worcestershire lost Richard Oliver who was caught in the deep off the first delivery of the match from spinner Matt Spriegel.

Tom Kohler-Cadmore, fresh from his maiden T20 fifty against Birmingham Bears, again looked in good form and hit four fours in his 20 from 12 balls.

But the return of Spriegel to the attack brought about his downfall as the 19-year-old came down the pitch and was stumped with the total on 35 in the fourth over.

Munro lofted Olly Stone for a massive six and the New Zealander cut David Willey for four to bring up the 50 in the sixth over.

The Rapids reached 52-2 at the end of the powerplay but without addition to the score Mitchell (17) was caught behind off a bottom edge to the first ball from Steven Crook.

Munro used the reverse sweep to pick up a six and a four off successive balls from James Middlebrook in an over costing 14 runs.

It became 70-4 when bowler Steven Crook followed through to run out Ross Whiteley (2) after he was stranded out of his ground.

Cox hit Crook for six over mid wicket and four backward of square and the 100th came up in the 12th over bowled by Muhammad Azharullah which cost 15 runs.

Munro was run out for 49 at 117-5 after digging out a yorker from David Willey who threw down the stumps at the bowler's end after the batsman attempted a quick single.

His innings contained three sixes and four fours and spanned just 30 balls.

The innings lost some of its momentum and Leach (5) was bowled attempting to cut Middlebrook and boundaries were hard to come by until Brett D'Oliveira pulled Olly Stone for six in the penultimate over.

Cox was trapped lbw by Azharullah for a fine 46 in the final over, D'Oliveira (15) was picked up at mid off and Jack Shantry was bowled by a full length delivery for a duck.

The Steelbacks only scored 14 runs off the opening three overs from Shantry and McClenaghan.

Leach made the first breakthrough in the final over of the poweplay when Willey was bowled for 19 as Northants reached 48-1 at the end of the initial six overs.

Choudhry came into the attack and bowled his excellent spell.

He held onto a superb return catch from Richard Levi (25) and the spinner broke through again when Kyle Coetzer (19) was caught at the second attempt by Mitchell at mid wicket.

Mitchell brought himself into the attack and in his first over caught and bowled Steven Crook (6). Then Adam Rossington (29) was deceived by a slower ball from Mitchell and adjudged lbw at 108-5 in the 16th over.

Mitchell picked up his third wicket in the same over when Rob Newton (1) became the third player to be caught and bowled in the Steelbacks innings.

McClenaghan returned to the attack and claimed his first Rapids wicket when Ben Duckett (18) perished to Joe Leach running in from the boundary.

Mitchell's fourth wicket arrived when James Middlebrook (2) was caught behind by Ben Cox and then the bowler stuck out his left hand to hold onto another superb return catch to dismiss Spriegel.

It was all over when Shantry accounted for Stone in the final over, caught by Colin Munro above his head running back, and a crucial win had been secured.