Wayne Madsen's brilliant 66 off 28 balls led in-form Derbyshire to a winning total as they completed a quickfire Vitality Blast double over Yorkshire with a rain-affected win at Headingley.
The Falcons, who won Saturday's North Group contest at Chesterfield when they scored 42 off the last three overs, won the rematch in Leeds by 77 runs.
After an hour's rain delay reduced the game to 17 overs a side, the visitors stormed to 179 for seven and defended it comfortably to win for the fourth time in eight matches this campaign - after starting with four losses.
Madsen hit 10 fours and two sixes in an innings which mixed power with innovation, highlighted by his two sixes off Azeem Rafiq's off-spin.
His first was smashed high over long-on into the top tier of the new stand at the Football End of Headingley, before a second was reverse-swept over wide third man.
New Zealand overseas fast bowler Lockie Ferguson then claimed three wickets for 21 runs and medium pacer Alex Hughes three for 12 from their three overs as the Vikings slipped to 102 all out, losing their last six wickets for 11 runs in three overs.
Derbyshire lost Billy Godleman to the first ball of the match, bowled having a swipe at David Willey.
But Calum MacLeod (28) and pinch-hitting Pakistan seamer Wahab Riaz got the innings moving, with the latter playing the lead role in a belligerent 42 off 30 balls.
The pair shared 66 in 6.4 overs before MacLeod holed out to deep midwicket to hand seam bowling all-rounder Jordan Thompson the first of his three wickets on his home debut.
Madsen built on that momentum in exhilarating style, reaching 50 off 22 balls before Riaz fell in similar fashion to MacLeod off Rafiq as the visitors totalled 114 for three in the 12th.
Madsen, 34, continued his onslaught before the Falcons lost four wickets for 30 in the last four overs, including Hardus Viljoen and Madsen - both caught off Thompson in the 14th over.
Adam Lyth and Tom Kohler-Cadmore hit sixes in the first two overs of Yorkshire's chase, the latter smashing Ravi Rampaul over midwicket and clearing the West Stand.
Both fell to Kiwi pace bowler Ferguson to further strengthen Derbyshire's hand at 37 for two in the fifth over - Kohler-Cadmore caught behind and Lyth at deep square-leg.
Hughes had Kane Williamson caught low down at cover in the next over, making it 42 for three - and from there it was always going to be an uphill task for the hosts.
Ferguson later had Gary Ballance caught at short fine-leg scooping, before Hughes claimed two of the last six wickets, seeing Tim Bresnan caught behind before bowling Thompson in the 13th over.
Yorkshire's fourth defeat also handed Derbyshire the double in this competition for the second successive year - and it is the first time they have beaten them in four matches in any format.
This was only the Vikings' third home defeat since the start of 2016 - but they have a chance to put things right on Tuesday when Leicestershire visit.