Sussex 203 (Hudson-Prentice 59, Harris 3-38, Swepson 3-52) and 273 for 9 (Carter 55*, Swepson 4-89) drew with Glamorgan 242 (Root 66, McAndrew 4-58) and 319 (Northeast 104, Carlson 59, McAndrew 4-47)
Sussex’s last pair survived 21.2 overs to save the game, Glamorgan left frustrated as they were one wicket short of leapfrogging their second-placed opponents in the table.
The visitors’ rearguard action kept them second in the table as this game finished in a nail-biting draw, after 15 overs were lost to rain in the morning.
Wicketkeeper Carter survived 149 deliveries, Shipley 56, after Nathan McAndrew’s earlier rapid 42 showed brief promise of Sussex chasing down the target, before the wickets started tumbling regularly.
Sussex nightwatcher Aristides Karvelas had said his side would go for victory, but he went early and the game slowed down with Tom Clark and Tom Alsop struggling to score runs from Swepson in particular.
Alsop was clearly a key wicket for the home side to target as the visitors reached lunch with just two down, but after the break James Harris pinned the skipper lbw from round the wicket.
He was replaced by all rounder McAndrew in a clear declaration of intent that Sussex were prepared to have a bit of a dash to try and win the game.
Clark survived a big lbw shout from Swepson, but then next ball the same sort of delivery was that little bit closer and he had to depart.
The aggression levels went up with McAndrew prepared to take on the bowling and more than happy to take the aerial route to the boundary whenever possible. He hit Swepson out of the attack to see the pace of McIlroy replacing him, but that hurried the Australian into a skied mis-hit off a shorter ball which was comfortably caught at mid on by Glamorgan captain Kiran Carlson.
That brought the end of an innings which brought 42 runs off 40 deliveries, the sort of rate which would have made things much more interesting if he had carried on.
Sussex continued to take a positive approach with James Coles leading the way, until he was impressively caught behind for 35 by wicket keeper Chris Cooke standing up to seamer McIlroy.
One of the concerns for Sussex fans was the relative inexperience of the Sussex middle order and teenager Danial Ibrahim was next to go, sweeping a leg side delivery from Swepson but top edging to Zain-ul-Hassan at backward square leg.
However the visitors maintained a positive approach, reaching tea with seven wickets down and still needed 154 to win.
Their eighth wicket fell after tea, Harris setting three men back on the hook and then yorking Fynn Hudson-Prentice with the middle stump coming out of the ground.
Oli Carter was dropped on 37 by Billy Root at square leg off McIlroy, but Root atoned by making no mistake with Jack Carson off the bowling of Timm van der Gugten to leave Glamorgan needing one more wicket for victory with more than 20 overs remaining.
They had one difficult chance, Carter slashing van der Gugten high to the right of Zain-ul-Hassan at first slip. Despite the regular appeals in the closing overs, that proved to be it for home hopes.