Luke Wright hit three sixes and seven fours as his swashbuckling 66 off 39 balls dented Glamorgan's NatWest T20 Blast quarter-final hopes and powered Sussex Sharks to a five-wicket win at the BrightonandHoveJobs.com County Ground.
Wright virtually settled the match, as Sussex chased down Glamorgan's 151 for eight, by clubbing Jacques Rudolph's leg-spin for three fours and a six in a 13th over that cost 19 runs.
The England limited-overs man fell to the first ball of the next over, with Dean Cosker taking a juggling catch at midwicket from a pull against Andrew Salter's off-spin.
But only another 36 runs were then required from 41 balls as Wright walked off to great acclaim from a near-5,000 crowd.
Matt Machan, with 33 not out from 35 deliveries, then eased Sussex home with nine balls to spare as they ended on 153 for five.
Sussex's fifth win of the group stage still keeps their mathematical chances of last eight qualification intact, while Glamorgan may live to regret their fourth defeat as they battle to get out of the fiercely-contested South Group.
Glamorgan, who would have gone second in the table if they had won, were also undone by Will Beer's leg-spin as his brilliant four-over spell of 3-14 pegged them back when they looked to be on course for a challenging total.
Having won the toss, Glamorgan were given a superb start by Rudolph and skipper Jim Allenby, on form the best opening pair in the Blast this season.
At the end of the six-over powerplay Glamorgan were 57 without loss, with Rudolph setting the tone by taking three fours from the opening over, bowled by left-arm seamer Lewis Hatchett.
The third over, from Chris Liddle, cost 12 more before Allenby pulled the returning Hatchett out of the ground for six.
Beer's introduction slowed Glamorgan's progress and his first victim was Allenby, bowled for 24 when inside-edging an attempted slog-sweep.
Mark Wallace was Beer's next scalp, bowled for three as he missed an ambitious reverse-sweep, and the 25-year-old tossed one up a little bit higher to have Stewart Walters smartly caught and bowled for a duck.
Big-hitting Chris Cooke holed out to Craig Cachopa at deep square-leg as he mishit a pull at Steffan Piolet's medium pace.
At 79 for four, in the 11th over, Glamorgan's innings was in danger of spluttering out, but a fifth-wicket stand of 50 between Rudolph and Murray Goodwin revived it.
The veteran Goodwin reached 35 from 24 balls against his former county, pulling a Piolet full-toss for six and plundering successive fours from off-spinner Chris Nash.
After Goodwin fell to the last ball of the 17th over, miscuing to long-on, Rudolph was bowled by Steve Magoffin for 62 off a thin inside edge.
Sussex lost Nash and Luke Wells early but Cachopa hit a six and three fours to impress in a quickfire 24, before being stumped advancing at Cosker's left-arm spin.
However, Wright was always in command.
Sussex captain Nash said: "It was nice to be able to win our last group home game. Our crowds have been brilliant all season for Twenty20, even though we haven't performed as well as we would have liked overall.
"I was also glad Will Beer was in at the end and hit the winning boundary. He has been exceptional with both ball and bat in this competition, and he deserved that moment of getting us over the line here."
Glamorgan skipper Allenby added: "I always thought our total was on the low side. Around 160 would have been par, but Will Beer bowled exceptionally well to peg us back and full credit to him for that.
"We are still in contention to finish in the top four in the group, however, and I'm happy with that with two games still to go."