A middle-order collapse from Durham allowed Lancashire to snatch a one-run victory in their NatWest T20 Blast North Group clash.
The hosts looked set to surpass Lancashire's total of 133-6 at Emirates Durham ICG with ease before losing three wickets for two runs in 11 balls during the latter stages of their chase.
That set up a tense finale, with four needed from the final ball, but Ryan Pringle was unable to put Kabir Ali's final delivery away to the boundary and Lancashire completed the narrowest of wins.
Lancashire chose to bat after winning the toss and set a middling target as Karl Brown top-scored with 61 from 51 balls before being removed by Chris Rushworth (2-25).
Jordan Clark was the next highest scorer for the visitors with 27 as Durham shared the wickets, with only Pringle not claiming a scalp.
In reply, Durham lost Mark Stoneman (12) in the third over but Calum MacLeod's 45 from 34 balls looked to have put the hosts in control.
But the tables were turned when Paul Collingwood (19) was quickly followed back to the pavilion by MacLeod and Gareth Breese (1) as Durham were left struggling on 100-6 with 23 balls remaining.
When Junaid Khan (3-21) bowled Muchall in the 19th over, Durham needed more than two runs a ball to win with only three wickets in hand.
That left Michael Richardson (12 not out) and Pringle (14no) at the crease, with 15 needed from the final over for victory. Richardson struck three from the first ball by Kabir Ali, with Pringle blasting a boundary with the next and then two runs and a single.
A single from the fifth ball of the over left Durham needing a boundary to win, but Pringle could only find two as Lancashire scraped home.
Also in the North Group on Thursday, Derbyshire's clash with Northamptonshire was abandoned without a ball being bowled.
The umpires decided that the outfield was unfit for play due to several wet areas and called off the game in Derby at 6.45pm.
The result meant Derbyshire picked up their first point in the tournament, the Falcons having lost their opening two matches.
The Steelbacks, meanwhile, stay unbeaten and have taken five points from their first three games.