Glamorgan 494 (Ingram 178, Byrom 176) and 141 for 5 (Northeast 45*, Carlson 45) beat Sussex 376 (Carter 185, Clark 55) and 258 (Carter 83, Rawlins 57) by five wickets
Glamorgan beat Sussex by five wickets as 12 wickets fell on a pulsating final day.
Oli Carter and Delray Rawlins had put on 104 for the sixth wicket after Sussex had lost two early, as they looked to settle the nerves, taking the lead into three figures just after lunch.
Glamorgan roared back into the contest with three wickets in five balls and bowled the south coast county out for 258, after they had been 220 for 5.
Set 141 to win from 43 overs, Glamorgan struggled against the new ball and fell to 9 for 3 with Sean Hunt picking up two early wickets. Sam Northeast and Kiran Carlson steadied the ship with a partnership of 76
Tim Seifert was the first wicket of the day as he slapped a full toss from Andrew Salter into the grateful hands of Carlson at midwicket. Michael Neser was then rewarded for a probing spell in the morning as he trapped Daniel Ibrahim lbw for just 5 with Sussex still trailing by two runs.
Carter once again showed his class with another well-compiled half-century before the break, backing up his first-innings century. Delray Rawlins joined Carter at the crease and rode his luck early, as Neser dropped a caught and bowled chance when he was on 13.
Sussex got to lunch at 183 for 5 and Rawlins soon reached a stylish half-century after the interval. The two compiled a sixth-wicket partnership of 104 and looked like they would pull their side towards a draw as Sussex were 220 for 5.
Glamorgan then blew the game wide open with three wickets in five balls. Colin Ingram came back into the attack and took the massive wicket of Carter, who swept another innocuous delivery straight to short fine leg for a well-made 83.
Andy Gorvin, the Covid substitute for Michael Hogan, then struck twice in the next over as he bowled Rawlins for 57 and had Henry Crocombe caught behind for a duck and Glamorgan were firmly in the ascendency as Sussex fell to 224 for 8.
Neser finished off the rest of the tail removing Jack Brooks for eight and Sean Hunt for two as Sussex were dismissed for 258 with Glamorgan requiring 141 runs to win from 43 overs.
A simple chase was turned on its head as the century makers from the Glamorgan first innings, Eddie Byrom and Colin Ingram, were removed by Brooks and Hunt for two and nought respectively, before Hunt bowled the Glamorgan skipper for seven.
Northeast and Carlson settled some nerves with their stand, then Carlson ran past a googly from Archie Lenham and was stumped for 45. It became five down when Billy Root was well caught by Seifert off the bowling of Brooks, with 22 runs required for victory
The batters then took 13 off the next over to make things a formality before Chris Cooke smashed Lenham through the covers to seal a memorable win at Sophia Gardens. Northeast finishing unbeaten on 45.
Glamorgan take 23 points away from the victory and leap to joint third in the LV= County Championship table.