Australian great Steve Smith struck fifty after a fiery spell from Ollie Robinson dismantled Glamorgan on day one at the 1st Central County Ground in Hove.
Robinson, rested for Sussex’s last match, returned to post figures of 4-29 as the visitors were all out for 123.
A month out from the first Ashes test match, the seamer dismissed Australia’s Marnus Labuschagne for one, pinning the right-hander lbw, with a length delivery that jagged in.
Kiran Carlson, Michael Neser and Timm van der Gugten all also fell to the Englishman as the visitors offered little resistance – skipper Carlson shouldering arms to a ball that crashed into his middle stump.
The rest of Sussex’s seam attack supported their talisman nicely. Greek international Ari Karvelas took three crucial wickets, finding the edges of opener Eddie Byrom and wicket-keeper Chris Cooke before cleaning up the Glamorgan tail.
Debutant opener, Zain Ul-Hassan made a fighting 22 before falling to the part-time seam of Tom Haines, who also claimed the wicket of Billy Root.
Prior to his dismissal, Root had been on the offensive, hitting four boundaries including two forceful drives off the bowling of Fynn Hudson-Prentice in the 17th over. He fell for 18 off 17 balls, bowled by an in-swinging delivery to which he played no shot.
Hudson-Prentice was the most expensive of the Sussex bowlers. The visitors took 37 runs from his seven overs. He did, however, remove the experienced Sam Northeast. The Glamorgan number four edged to James Coles at third slip.
When it was Sussex’s turn to reply, Smith was the pick of the home batters as he made his final County Championship appearance of the season.
The Australian went about his work expertly, leaving anything treacherous while cashing in on loose balls. Two picture perfect drives in the 45th over took him to the brink of his half-century which he reached with a back-foot punch soon after. His fifty came off 98 balls.
Earlier, Tom Haines and Ali Orr made a fast start for the home side. The former struck three brutal boundaries off Timm van der Gugten in the second over. While the latter took a particular liking to Michael Neser, punishing the Australian with twin flamboyant drives.
The stand reached 76 before Glamorgan fought back, claiming three wickets for only six runs.
First, Orr was bowled by Jamie McIlroy, the 22-year-old shouldering arms to depart for a stylish 40 from 42 balls. Tom Alsop and Cheteshwar Pujara then both fell quickly, each lbw to the fired up Neser. Pujara was out for his first Sussex duck.
Now joined by Smith, Haines batted on. After crashing McIlroy for a couple of boundaries, he reached fifty with a glorious back-foot punch in the 27th over. The seamer would have his revenge, however, as Haines edged to slip eight overs later – out for 58 off 81 balls.
McIlroy was the pick of Glamorgan’s seamers, striking twice to claim figures of 2-47 from his 14 overs.
As the day’s end drew closer, new man James Coles eagerly attacked the ageing ball, an imperious pull shot off Ul-Hassan signalling his intent. He too ticked along and soon reached fifty.
At the close of play Sussex are 221 for 4, with Steve Smith on 68* and James Coles 50*. They lead Glamorgan by 98 runs.
