Durham Dynamos took over from visitors Hampshire Royals at the top of Yorkshire Bank 40 Group B with a six-wicket victory at the Emirates Durham ICG.
With coach Geoff Cook still in a critical condition following his heart attack on Thursday, his team romped to their fourth successive win in the competition with 2.4 overs to spare.
Despite conceding 93 off the last 10 overs, Durham restricted the holders to 224 for nine and lost acting captain Mark Stoneman in the first over of their reply.
A brief shower with the score on 55 for one in the 13th over reduced the target to 218 in 38 overs and, by the time Phil Mustard and Scott Borthwick had put on 164 for the second wicket, victory was a formality.
Mustard was dropped on 11 at slip by Sean Ervine off Pakistani left-arm paceman Sohail Tanvir and Borthwick survived a return chance to James Vince on 12.
Mustard went on to make 92 off 90 balls and Borthwick registered his maiden one-day fifty in scoring 80 off 82 deliveries before holing out with 17 needed.
Borthwick hit sixes off both left-arm spinners, Danny Briggs and Liam Dawson, who had combined figures of none for 85 in 11 overs.
Tanvir took all four wickets to fall, producing excellent deliveries to bowl Stoneman and Ben Stokes. But only three were needed when he nipped one back off the pitch to breach Stokes' defence and Collingwood saw Durham home with an unbeaten 32.
Hampshire were not helped by Dimitri Mascarenhas being unable to bowl following a back spasm, while Michael Carberry went for an X-ray after damaging a thumb.
For Durham, Chris Rushworth bowled with great control to take 5-42 after Hampshire were put in and the target looked like being much lower until Dawson thrashed 69 off 46 balls.
The openers put on 23 before Vince drove to mid-off and Carberry was caught at leg gully, deliberately placed for the miscued pull.
Jimmy Adams and Neil McKenzie carefully added 34 in 11 overs before the South African tried to flip a straight ball from Collingwood to fine-leg and was lbw for 18.
There was a second wicket for Collingwood when Adams holed out to Stokes at deep midwicket after making 32 off 50 balls.
That brought in Dawson at 112 for four in the 27th over and four overs later he began the late onslaught by sweeping a six as Collingwood's final over cost 12 and left him with 2-44.
The last four overs yielded 46 with Dawson driving two successive balls from Stokes for six. The first took him to 50 off 37 balls.
Stokes' first four overs were tight but he finished with 1-56 on what was not a good day for either him or Briggs ahead of teaming up with the England Twenty20 squad this week.