Yorkshire 281 for 5 (Whiteman 94, Wharton 75, Hill 63) beat Derbyshire 278 for 8 (Andersson 67, Came 58, Cliff 3-57) by five wickets
Sam Whiteman's calm 94 off 98 balls helped Yorkshire prevail by five wickets with four balls left chasing 279 to beat Derbyshire at Scarborough and move to the verge of Metro Bank One-Day knockout qualification.
Experienced Doncaster-born Australian Whiteman shared a fourth-wicket 107 with James Wharton, who contributed 75 to a recovery from 57 for 3 as Yorkshire won for the fifth time in seven matches in Group B.
Allrounder George Hill also had a good day with two wickets and 63 not out off 49 as a fourth defeat all but ends Derbyshire's hopes. He and Whiteman shared a decisive fifth-wicket 101.
Derbyshire will be mighty frustrated at not posting many more than 278 for 8 having been 140 without loss after 26 overs, with Harry Came and Martin Andersson going well. But both fell in a Jafer Chohan over for 58 and 67, and fast bowler Ben Cliff finished with 3 for 57 from nine overs as the innings subsided.
Having been inserted, Derbyshire made the dream start on a pitch with bounce and movement.
Hill sent a short ball soaring over wicketkeeper Fin Bean's head for five wides, and Will Bennison then let an Andersson pull at leg-spinner Chohan on 40 burst through his hands on the deep square-leg boundary.
Andersson and Came found the perfect balance between caution on a pitch with extra bounce and aggression in reaching their fifties off 66 and 69 balls respectively.
However, they both fell to Chohan - back from The Hundred to make his county List A debut - in the 27th over, Came caught at long-off and Andersson at midwicket.
Dom Bess, Cliff and Hill then all struck as Derbyshire lost momentum - a reverse sweeping Wayne Madsen well caught one-handed at backward point by Bennison - and were 239 for six going into the final five overs.
Cliff cemented his place at the top of the competition's leading wicket-taker's list and now has 18.
Derbyshire, who left out England spinner Shoaib Bashir, then gave themselves an early boost with the ball as Aitchison and Nick Potts removed openers Will Luxton and Adam Lyth as Yorkshire fell to 22 for two. Lyth could only fend a fearsome short ball to second slip.
Aitchison struck again to remove Bennison with the score on 57 before Wharton and Whiteman united.
This was a game in which no batter ever looked settled.
Wharton reached his fifty off 66 balls, and when Whiteman got to his off 62 balls Yorkshire were 163 for three in the 35th over. But Wharton cut Potts to point moments later.
The target became 91 off the last 10 overs at 188 for 4.
Hill was inventive, and 42 came from four overs from the end of the 41st onwards to put Yorkshire ahead at 235 for 4.
Hill reached his fifty off 42 balls before Whiteman was caught behind down leg off Potts with 14 needed off 11.
Bean hit the winning runs with two needed off the last over.
