Wes Durston inspired Derbyshire to a second victory in as many days as the Falcons beat Yorkshire by 52 runs at Headingley.
Chasing a 245-8, the hosts slumped to 193 all out with one over remaining in the Clydesdale Bank 40 League encounter.
It left the rock bottom Tykes still seeking their first win in the competition in what has been a generally depressing start to the season, while the Falcons are flying high at the top of Group A after also defeating Sussex on Sunday.
The visitors owed a great deal to Durston, who contributed 95 to his side's total and then took 3-25.
In the run chase, Yorkshire skipper Andrew Gale and Adam Lyth started out promisingly but after they had added 35 in seven overs, Lyth fell to a great two-handed catch by Garry Park flinging himself to his right at point.
But it was the departure of Gale, for 74, which really spelled the end for his team after he had faced 86 balls and struck four fours and two sixes, Durston scooping up a low return catch which television replays confirmed had carried to the bowler.