Leicestershire 144 for 8 (Cosgrove 33, Collingwood 4-24) beat Durham 117 for 8 (Coughlin 42*, Parkinson 3-20) by 27 runs
North group leaders Leicestershire made it four wins out of four, all away from home, in the NatWest T20 Blast when they beat Durham by 27 runs at Chester-le-Street.
The Foxes appeared to have made a hash of their innings as they subsided from 100 for 2 in the 12th over to 123 for 8 after 18.
The return of quicker bowlers allowed Matt Pillans to strike two fours and there were also four leg byes as 21 came off the last two overs to leave them on 144 for 8.
It proved more than enough as Leicestershire learnt from the success of Durham's spinners for Colin Ackerman and Callum Parkinson to take two wickets each in reducing the Jets to 31 for 5.
Left-armer Parkinson added a third to end a stand of 30 when he bowled Usman Arshad and Durham finished on 117 for 8.
With the Sky cameras present on a sunny evening, Durham came under fire after choosing to bowl. The visitors' top three all made rapid progress, but Mark Cosgrove's 33 was the top score.
The failures of the middle order put him under pressure and he holed out at deep midwicket in the 16th over to become one of four victims for Paul Collingwood.
Seven overs of offspin produced 3 for 33 with Ryan Pringle taking 2 for 22 and Adam Hickey 1 for 11 in three.
They hauled Durham back into the game after Luke Ronchi and Cameron Delport took 14 off Chris Rushworth's opening over and had 37 on the board after four.
Delport departed for 29 when he sliced Rushworth to backward point, then Cosgrove opened the face and ran the first ball he faced to the third man boundary.
Ronchi reached 32 off 22 balls before dragging a Collingwood slower ball to wide long-on, where Pringle held the catch before conceding only three runs off the tenth over.
Pringle then struck twice in the 12th as a smart leg-side stumping by Stuart Poynter got rid of Ackerman then Ned Eckersley lofted to long-off.
That double blow set the collapse in motion, but Clint McKay followed his 5 for 11 in Leicestershire's last game by striking with the first ball of Durham's reply.
Left-hander Hickey reached for a wide one and sliced to Delport at point and when Ackerman came on for the fourth over Clark pulled his first ball straight to deep midwicket.
Michael Richardson chopped an attempted cut into his stumps and Parkinson took the next three wickets.
Jack Burnham attempted a ramp to fine leg and was bowled, Collingwood chipped to deep mid-on and Arshad was bowled for 27 when Parkinson came back for his final over, the 15th.
It was left to skipper Paul Coughlin to salvage some pride for Durham with an unbeaten 42.