Durham 147 beat Yorkshire 104 (Potts 3-14, Coughlin 3-22) by 43 runs
Durham won their third successive Vitality Blast game by beating Yorkshire in a low-scoring affair at Emerald Headingley, maintaining their hopes of quarter-final qualification.
The visitors defended a 148 target against the under-strength Vikings, whose knockout hopes are all but over after a third straight defeat in which they were bowled out for 104 in the 17th over, losing by 43 runs.
Durham have seven points from eight games and jump to third in the North, three points behind Lancashire in second - their next opponents at Emirates Old Trafford on Friday. The best two third-placed finishers from the North, Central and South also qualify. Yorkshire have six points from eight games.
The hosts were hurt by the continued coronavirus-related absence of Matthew Fisher, Tom Kohler-Cadmore, Josh Poysden and captain David Willey, who missed their second game in three days after the latter and his wife Carolynne tested positive.
However, all players met up outside of cricket on Saturday and must undergo the 14-day self isolation period. They are unavailable for the rest of the group stage.
Durham reached 40 without loss after four overs, only to slip to 147 all out as South African fast bowler Duanne Olivier claimed 2 for 16 from four overs. In reply, Yorkshire lost England's Dawid Malan for a golden duck and failed to recover.
Yorkshire, for whom stand-in skipper Adam Lyth and Jordan Thompson also claimed two wickets, and Durham came into this game in contrasting form.
And it was buoyant Durham who made a fast start having been inserted, with Graham Clark hitting three fours and a six in a brisk 28, the top score in the innings.
But Clark and opening partner Alex Lees fell within two overs of each other - Lees caught and bowled by Lyth's offspin and Clark caught at long-on off the same bowler as the score fell to 57 for 2 in the eighth.
Ben Raine maintained Durham's momentum with successive leg-side sixes to end the eighth over, but he was caught behind cutting at another offspinner, Jack Shutt - 78 for 3 in the 10th. Farhaan Behardien then dragged compatriot Olivier to mid-on in the 11th, leaving the visitors at 81 for 4.
David Bedingham was caught at deep mid-wicket off Thompson's seamers, undermining Durham's chances of reaching 150.
Brydon Carse counter-punched with a couple of lusty sixes down the ground off Shutt and Thompson, only to be caught behind the ball after hitting the second six as the score fell to 110 for 6 after 15.
Olivier further applied the brakes by getting Coughlin caught at mid-off in the 18th before Liam Trevaskis was run out in the 19th, in which Ben Coad also had Matty Potts caught at long-on. Scott Steel was also run out in the last over.
But that was far from the end of the drama. Lyth cut the first two legitimate balls of the innings from left-arm spinner Trevaskis for four, only to miscue Potts to mid-on in the second.
Next ball Malan chopped on, and when Harry Brook also miscued the same bowler to mid-on in the fourth, Yorkshire were 22 for 3 with their big guns gone.
Durham captain Nathan Rimmington then trapped Jonny Tattersall lbw as the score fell to 48 for 4 in the seventh, with 100 runs still required.
Will Fraine top-scored with 28, only for him and George Hill to fall in successive deliveries in the 10th and 11th overs, leaving the score at 73 for 6. Hill was bowled by Coughlin and Fraine caught behind off Carse.
The end came very quickly from there as James Wharton chipped Coughlin to cover. The same bowler later got Thompson caught in the deep.
Either side of the Thompson wicket, wily Trevaskis had Ben Coad stumped and Olivier bowled, sealing the win with 20 balls to spare.