Chaminda Vaas starred with bat and ball against his old county Worcestershire as Northants finally broke this year's FP t20 duck at the fourth attempt.
Vaas hit a fluent 54, including three huge sixes, as a makeshift opener for the hosts, who went on to post a total of 143-8 from their 20 overs.
He then went on to grab two wickets as Northants restricted the visitors to 122-8, Ben Scott (23no) top scoring.
But Northants remain bottom of the group despite their 21-run victory.
Worcestershire youngster Jack Shantry had been the pick of their attack, taking 2-24.
Northants won the toss and chose to bat in glorious conditions, former New Zealand international Lou Vincent, one of three former Worcestershire players up against their old team, making a breezy 18 before hitting James Cameron to Shantry at mid-on.
Cameron then dropped Vaas twice, first at deep extra cover then deep mid-wicket, both off Australia spinner Steve Smith, as Vaas and Ireland wicketkeeper Niall O'Brien added 71 between them.
Vaas went past 50 off 39 balls by smashing Gareth Andrew for six over mid-wicket but perished by blasting the same bowler to Smith at long-off.
O'Brien (31) departed soon after when his off-stump was taken out by Moeen Ali before captain Andrew Hall smashed stand-in Worcestershire skipper Daryl Mitchell to deep mid-wicket.
Chasing 144, Worcestershire got off to a bad start when Jack Manuel, on his senior debut, launched Vaas to deep square leg.
Ex-skipper Boje then bowled Phil Jaques for 10 and an awful running mix-up in the ninth over involving Moeen and Kervezee led to a sorry procession.