A virtuoso all-round performance from Moeen Ali ensured Worcestershire ended their Friends Life t20 campaign in style against Mid/West/Wales group winners Northamptonshire.
Ali blasted 72 off just 45 balls, including 40 off the last 11 deliveries he faced, as the already-eliminated Royals posted an imposing 182-6 from their 20 overs.
The Steelbacks, whose quarter final place was already assured, fell 37 runs short of their target with Ali returning career-best Twenty20 figures of 5-34 to inflict the hosts' first home defeat in the competition.
Worcestershire won the toss and chose to bat and wicketkeeper Ben Cox was the first to fall in the seventh over when he was trapped lbw by Matthew Spriegel after making 27.
Alexei Kervezee (one) was then caught and bowled by the same man five balls later before the Royals' captain Daryl Mitchell was run out on 19 by his Northants counterpart Alex Wakely at extra cover.
But Ali was to guide his side towards an impressive total by surging past 50 off 39 balls, although he eventually holed out by smashing Steven Crook to Australia international Cameron White at long on.
This broke up a 55-run stand off just four overs with Olly Stone then taking out the leg stump of Ali's partner Ross Whiteley (12). Stone's yorker then sent Gareth Andrew's middle stump spinning to dismiss him on 19 in the penultimate over.
Chasing 183, the Steelbacks started confidently with Richard Levi plundering 31 off 23 balls before launching Ali to Kervezee at deep midwicket to break an opening partnership of 54 with Kyle Coetzer.
Coetzer followed tamely for 23 when he was taken by Mitchell at midwicket off Ali, who then bowled Wakely (17).
He then claimed his fourth wicket in four overs when his delivery clipped Crook's off stump before completing his first-ever five-wicket haul in Twenty20 cricket when Cox stumped Spriegel.
With the match slipping away from them, Northants lost White for 30 when he hammered Brett D'Oliveira to Charlie Morris at long off with two overs left, but a quarter final at Wantage Road awaits for them next week.