Allenby and Cosker to the fore
A Jim Allenby half-century and 4-33 from Dean Cosker helped Glamorgan to only their second Clydesdale Bank 40 victory of the season, a three-wicket success over Sussex at Swansea.
Defeat is a setback to Sussex's chances of reaching the semi-finals and was not the best way to warm up for tomorrow's Friends Provident t20 quarter-final against Nottinghamshire at Trent Bridge.
Sussex, who sank to their third defeat, were hampered by the absence of Matthew Prior, who is on England duty, and injured duo Luke Wright and Yasir Arafat as they were restricted to 203 for seven after winning the toss.
Glamorgan - minus Mark Cosgrove, who dislocated a finger fielding - made something of a meal of their reply, not helped by some poor running between the wickets and dubious shot selection.
However, they squeezed to their target with only four balls to spare, helped to the winning line by a 60-run partnership between Mark Wallace and Ben Wright.
Sussex made a decent start but Ed Joyce was bowled through the gate by Will Owen and Joe Gatting fell to a sharp stumping by wicketkeeper Mark Wallace off Cosker.
Chris Nash's 85 from 88 balls - his fifty came off 58 balls - was the backbone of Sussex's innings and a useful effort in the context of the rest of the innings.
Sussex's demise occurred during the batting powerplay when they lost four wickets for seven runs in only 13 balls.
They were going along well at 159 for two in the 31st over, with Nash and Murray Goodwin’s stand worth 92, only to slump to 166 for six.
The main damage was done by left-arm spinner Cosker, who claimed three of his four wickets in the space of eight balls.
He had Goodwin caught at backward point reverse-sweeping and, after Nash was caught in the deep off Owen, Cosker struck twice in three balls, taking a return catch to account for Michael Yardy and bowling Andrew Hodd, his 200th victim in one-day cricket.
Allenby, who went to 50 from 51 balls, gave Glamorgan a more than solid start in partnerships with opener Robert Croft and Will Bragg of 33 and 74 respectively.
During the Allenby-Bragg alliance, slow left-armer Monty Panesar went for 31 from his opening three overs.
But Glamorgan's good start was not helped that they subsided from 107 for one to 141 for five, which put pressure on the lower order.
Wallace and Wright took Glamorgan towards victory but were both dismissed in consecutive overs, leaving Cosker to strike the winning runs from the second ball of the final over.