Adam Lyth's half-century helped Yorkshire to a five-wicket victory over the Unicorns in a low-scoring YB40 affair at Chesterfield.
The Vikings have started their 40-over campaign in dreadful form with two successive defeats, but chased down the Unicorns' 189-9 in the penultimate over to get off the mark after making 191-5.
Richard Pyrah bagged three wickets as Yorkshire's bowlers restricted the Unicorns, combining with Adil Rashid and Steve Patterson to reduce them to 103-6 after 29 overs.
Only some late hitting from number nine Anuerin Norman boosted the Unicorns' score as he finished with an unbeaten 38 from just 26 balls.
Pyrah finished with figures of 3-34 from his eight overs, with Rashid taking 2-27 and Patterson 2-35, and although Yorkshire had let the Unicorns off the hook slightly their victory target was still very gettable.
The run chase did not start well though for Yorkshire as they lost both openers, Pyrah and Andrew Gale, to Warren Lee as the Unicorns reduced them to 24-2 early on.
A fifty partnership between Phil Jaques (25) and Gary Balance (44) helped get Yorkshire back on track, although they lost both men quickly to get two new batsmen at the crease at 88-4.
Rashid and Lyth combined for 52 though before the spinner out for 32, but Lyth continued to see Yorkshire home as he made 58 from just 60 balls with five fours and three sixes in his innings.
Yorkshire got home on the penultimate ball of the penultimate over to finally get their YB40 campaign underway with a first win in Group C.