Clark (87 from 57 balls) and Bedingham (78 from 42) laid the platform for Durham, hitting four sixes each in a 109-run stand as Durham ran up 218-3 – their highest T20 total against Lancashire.
Durham then took wickets at regular intervals, spearheaded by an unbelievable caught-and-bowled from Paul Coughlin to remove Matty Hurst and three wickets for Lancashire old boy Callum Parkinson.
From 115-6, some heroic lower-order hitting from Chris Green (38), George Balderson (37no) and Jack Blatherwick (17) almost got Lancs home, but they fell just short on 216-8.
Northants improved their hopes of making the knockout stages as they completed a double over Worcestershire to make it four wins in six matches.
But Worcestershire’s fourth straight defeat leaves them up against it.
On the two-paced hybrid New Road pitch, the visitors had a stand of 75 between Matthew Breetzke (52) and Sikandar Raza (43) to thank for reaching 143-6.
Although Bears old boy Ethan Brookes hit 42, his joint highest T20 score, and skipper Brett D’Oliveira made 34, the hosts finished short on 132-7 – chiefly stemmed by Ben Sanderson’s 3-16.
