A rapid half-century by Steven Crook gave Northants Steelbacks the platform to open their Yorkshire Bank 40 account for the season with a 42-run win against Worcestershire Royals at New Road.
The home side only had themselves to blame as they spilled four chances - including one from Crook when he had made 10 - and the all-rounder made them pay by charging to an unbeaten 61 from 42 balls.
Crook's blitz, bringing seven fours and two sixes over the longest boundary at midwicket, helped the Steelbacks to a match-winning total of 219 for six. They added 61 in the last five overs.
This gave Worcestershire too much to do on a tricky pitch and they were dismissed for 177 in the 38th over despite Thilan Samaraweera's masterclass in one-day batting.
The 36-year-old Sri Lankan caressed the ball around the field, hitting only nine fours in making 78 from 81 balls, but the chase was over when he became the first of two lbw dismissals in as many deliveries from former Worcestershire all-rounder Andrew Hall.
Northants’ fielding was top-notch throughout and they delivered the most decisive spells with the ball. David Willey, who finished with 3-28, broke through at the top order and Matthew Spriegel took wickets in successive overs before completing figures of 3-29.
Samaraweera gave his side hope in stands of 53 with Daryl Mitchell and 58 with Gareth Andrew, but it was never easy to get the ball away on a sluggish surface.
Andrew was the big threat to Northants heading into the closing overs but, after driving one six off Crook, the left-hander was well caught by Kyle Coetzer as he speared a shot from Trent Copeland low to point.
In difficult conditions for the big-hitters, Crook was the exception in having the power to hit through the line in making his second List A fifty for the county.
Northants' openers had earlier kept things ticking over in a partnership of 62 before Brett D'Oliveira had a hand in their dismissals, taking a simple catch from David Sales at mid-on and bowling Rob Newton as the batsman attempted to cut.
Alex Wakely played well for 35 before falling to Jack Shantry, and off-spinner Moeen Ali produced the ball of the day, which turned and clipped the top of Spriegel's off stump for one of his three wickets.
However, Moeen's last over, costing 18 runs, was crucial as Willey and Crook cleared the ropes.