Glamorgan opened their campaign in Group C of the Yorkshire Bank 40 with a 28-run victory over Yorkshire at Colwyn Bay.
Skipper Marcus North made 68 to steer the hosts to a highly-competitive 285-7, a total Yorkshire could not surpass despite a half-century from Jonny Bairstow. They were eventually bowled out for 257.
Will Bragg (50) and Chris Cooke (58) gave Glamorgan a great platform after they had chosen to bat first, with the Welsh county bringing up their century in the 16th over.
North became the third home batsman to reach 50 when he struck his fifth boundary before eventually offering a return catch to Richard Pyrah, leaving the score on 245-5.
However Murray Goodwin led the acceleration in the closing stages, making 45 from 28 balls. Pyrah removed both Goodwin and Graham Wagg with successive balls to finish as the pick of the Yorkshire bowlers with 4-43.
The Vikings' run chase suffered a shocking start when Wagg dismissed both Phil Jaques and Joe Root in the
space of three balls in the second over.
Gary Ballance and Yorkshire skipper Andrew Gale began patiently rebuilding in a third-wicket stand worth 92, though they were only able to muster 38 runs from the opening 10 overs.
Dean Cosker ended the alliance when he had Ballance stumped off a wide with his first ball for an even 50, while Gale also fell to the same bowler for 65.
Bairstow reached a 34-ball 50 with seven fours and a six but Michael Hogan (3-29) returned to the attack to dismiss the England international courtesy of a catch by Will Owen.
Adil Rashid did his best with 42 not out from 28 balls but despite some average Glamorgan bowling he ran out of partners, the innings coming to an end with 10 deliveries to spare.