Spinner Dean Cosker claimed four wickets as Glamorgan beat Gloucestershire by four wickets in their Clydesdale Bank 40 Group C clash.
Glamorgan restricted the Gladiators to 154-8 on a slow wicket at the Swalec Stadium and the Dragons knocked off the required runs with 10 balls to spare.
The reply was underpinned by Glamorgan opener Gareth Rees, who struck his third-consecutive half-century.
Graham Wagg's attacking 22 from 23 balls helped Glamorgan over the line.
Rees was the mainstay of the innings, striking his 50 from 84 balls with just three fours.
He lost partners at regular intervals including skipper Alviro Petersen, who had his off stump pegged back by David Payne, and Jim Allenby - who was adjudged leg before - reverse sweeping off-spinner Jack Taylor.
The Welsh county then lost Stewart Walters (four) and Ben Wright (nine) as they were both caught at midwicket.
But an attacking innings from Wagg helped Glamorgan towards their target before being the victim of a brilliant catch by Kevin O'Brien.
Rees, meanwhile, ended unbeaten on 59 from 100 balls.
Despite winning the toss and opting to bat, the Gladiators found themselves on the back foot as they were reduced to 20-2 earlier in the day.
They got off to a poor start when opener Ian Cockbain was run out from the final ball of the first over at the bowler's end by a brilliant throw from Rees, with the total still on nought.
Rees was in the action again when he caught Ed Young, who miscued an attempted drive off James Harris to mid-on, and Will Owen then trapped Alex Gidman leg before with a well-disguised slower ball.
From 44-3 the Gladiators slipped to 63-4 when Cosker claimed his first victim in the 20th over by bowling Kane Williamson.
Much then depended on new signing O'Brien, who scored the fastest-ever World Cup century against England in March, but the Irishman lasted only four balls before he too was bowled by Cosker.
Cosker's purple patch continued when Chris Taylor holed out to Walters to leave the Gladiators on 84-6.
Gloucestershire were finding runs hard to come by and they only reached the 100-mark at the end of the 33rd over, and the first boundary for 26 overs came when Jon Batty swept Cosker for four.
But the spinner had his revenge in his next over by trapping Batty lbw leg to finish with four for 30 from his eight overs.
Harris then got rid of Richard Dawson late on in the Gloucestershire innings and their total never looked like being enough.