An opening stand of 87 with Luke Wells was broken by Potts before lunch but Lancashire pushed on again as Josh Bohannon joined Jennings in the middle.
With the sun breaking through and another partnership building, the home side looked well set, only for Stokes to find the breakthrough with a seemingly unthreatening short ball that Bohannon top-edged to deep backward square.
Jennings kicked on to bring up his second hundred of the season, from 138 balls, but he fell to Callum Parkinson soon after as wickets began to tumble at regular intervals.
Tom Bruce made 46 before he popped up a simple return catch to Stokes as Durham worked their way into the tail.
Lancashire slipped to 303-8 but Mahmood’s rally dragged them to another batting bonus point before he and Nathan Lyon batted out the last couple of overs.
