Ganguly bowled a tight leash and took a wicket for 21 runs in his four overs as Northants restricted their hosts to a paltry 86.
In reply, the Northants romped home with 4.3 overs and nine wickets intact. Ganguly made unbeaten 44 runs (53b, 5x4) and shared a 68-run partnership with David Sales (34).
Infact at one stage, Worcestershire were looking down the barrel after Matt Nicholson and Ben Phillips reduced them to 18 for six.
However, Zaheer Khan and the tail conjured up a slight recovery.
Coming at number nine Zaheer top scored with 26 off 21 balls (4x4).
Worcestershire have now lost their opening three matches and are firmly anchored at the foot of the Midlands/West/Wales Division.