Australian fast bowler Mitchell Starc took three wickets on his Yorkshire debut, but it was Gary Ballance's 77 that propelled the home side to a seven-wicket win in the Clydesdale Bank 40 encounter with Derbyshire at Headingley.
Ballance, in prime form at the moment, timed his innings to perfection as Yorkshire reached their 220-run target with 14 balls to spare.
The left-hander faced 60 deliveries and crashed six fours and four sixes, putting on 69 for the third wicket with Phil Jaques and an unbroken 70 for the fourth with Joe Root.
All of Yorkshire's five batsmen made telling contributions, skipper Andrew Gale (33) and Adam Lyth (31) sharing an opening stand of 56 and Jaques and Root later weighing in with 47 and 28 not out respectively.
Yorkshire's target turned out to be a lot easier than appeared likely while Derbyshire's openers, Chesney Hughes and Martin Guptill, were putting together a rousing partnership of 137 in 25 overs.
But once they had been parted, Yorkshire tightened the screw to such an extent that Derbyshire could only add 82 from 15 overs, during which time they lost eight wickets.
Hughes was first to go, bowled leg stump by Moin Ashraf for 50 from 73 balls with four boundaries, but it was Guptill who provided the real firepower with his 89 from 83 deliveries with four fours and five sixes, most of them coming from full-blooded drives.
Confident batting by Hughes and Guptill had denied Starc a wicket in his opening burst of five overs but he came back strongly later on to claim three for 11 in his second spell.
His first wicket for Yorkshire was that of Ross Whiteley who was held on the cover boundary by Lyth before Dan Redfern was caught behind attempting an audacious reverse paddle.
Starc struck again with the final ball of the innings which knocked back Tom Poynton's stumps as he went for a wild swing.