Northants stifled Warwickshire to claim a 24-run win at Edgbaston and maintain their 100% record in the Twenty20 Cup.
After winning the toss, the visitors amassed 155-7 thanks mainly to 59 from Rob White and 28 from Riki Wessels.
The home side started well in reply, with opener Jonathan Trott (44) helping them to 95-2.
But when he was caught by Steven Crook off the bowling of David Willey, Warwickshire lost their way and could only close on 131-6.
Northants sit top of the Mid/West/Wales Division with eight points from four matches, two points ahead of Somerset.
Warwickshire are third with four points, having won two and lost three in their five matches.