Sussex captain Luke Wright led by example at Sophia Gardens by striking 88 from 53 balls, as his team gained their second win from two games and lead the Southern Group after an impressive all-round performance.
After scoring 173 for 4, with Colin Ingram top scoring with an undefeated 81, Glamorgan were let down by some poor bowling, as Wright and Laurie Evans shared a match winning partnership of 123 in just 12.4 overs.
Needing to score at 8.6 runs an over, Wright began with a flurry of boundaries although he lost his opening partner Phil Salt in the fourth over, who, attempting to pull a short ball from Michael Hogan, edged to the wicketkeeper.
Wright then greeted Graham Wagg by driving him straight for six, followed by a rasping cover drive for four, and when Wagg was taken off after one over, he had conceded 16 runs. The Sussex captain raced to his fifty from only 33 balls, and his team were well placed at the halfway stage on 89 for 1.
Wright was well supported by Evans, who also punished some indifferent bowling from Glamorgan, who bowled far too short on a good pitch, and at 109 for 1 at the end of the twelfth over, were coasting to victory.
The home team then suffered a setback, when Shaun Marsh, their Australian overseas batsman, dived in an attempt to stop a fierce drive from Wright, but landed on his shoulder, and had to leave the field in some pain.
Sussex required 41 from the final 5 overs, but there was no respite for the bowlers as Wright drove Ingram and hooked Wagg for sixes, before holing out on the mid-wicket boundary. Evans settled the issue by striking Hogan for two sixes in the 18th over, and there were eight balls remaining when Tom Bruce struck the winning runs.
Glamorgan’s innings was built around a typically aggressive innings from Colin Ingram who struck from balls, and the captain was well supported by David Lloyd, who made 33- including a straight six off Rashid Khan, who again bowled economically and picked up two wickets.
Glamorgan were 59 for 3 after nine overs, after Shaun Marsh had pulled a long hop from Joffra Archer to deep mid- wicket, Usman Khawaja mishit to deep cover, and Aneurin Donald holed out to Khan at long off.
Ingram was then soon into his stride, and played Khan – who was in the same side, The Adelaide Strikers, that won the Big Bash Australia last winter- with respect, as the Afghan spinner ended with the creditable figures of 2/27 from his four overs.
Ingram the accelerated in the final overs, as Ollie Robinson and David Wiese were struck for two huge sixes over long on as 53 runs were added in the final five overs, with Ingram undefeated on 81, which came from 44 balls, which included seven fours and four sixes.
Watch Sussex football fans react to England's quarter-final win over Sweden
Sussex Cricket League: Brighton beat Cuckfield by just ONE run in thriller
Five-wicket hero Wiese toasts super Sharks start in T20