|Specsavers County Championship Division Two, The SSE Swalec, day one|
|Glamorgan 252 (60.1 ov): Wallace 61, Wagg 57, Archer 4-91, Wiese 3-52|
|Sussex 111-1 (35 ov): Nash 62*, Joyce 47|
|Glamorgan 2 pts, Sussex 3 pts|
Sussex had the better of day one as they reached 111-1 in reply to Glamorgan's 252 all out after a frantic start in Cardiff.
Glamorgan collapsed to 56-5, but partly recovered thanks to breezy half-centuries from Graham Wagg (57) and Mark Wallace (61).
Youngster Jofra Archer with his Championship best of 4-91 was the most successful of the visitors' bowlers.
Ed Joyce passed 1,000 Championship runs in 2016 in the Sussex reply.
His knock of 47 and Chris Nash's unbeaten 62 not out put the home batting effort into sharp perspective as they batted through most of the evening session with a stand of 111.
Glamorgan were quickly in trouble after being asked to bat, with the top order's struggles continuing on a green-tinged pitch.
Sussex's seamers found the edge of the bat at regular intervals with Archer, Steve Magoffin (2-48) and David Wiese (3-52) all threatening.
Wagg and Wallace earned some respectability, while Owen Morgan (32 not out) and Michael Hogan (19) scrambled a second bonus point.
Glamorgan top scorer Mark Wallace told BBC Wales Sport:
"It was tough conditions batting first after they chucked us in without a toss, they bowled really well and 252 all out is a bit shy of where we could have been.
"It could have been around 300, but then they batted really well and they're in the box-seat at the moment but there's plenty of cricket left.
"Ideally either myself or Waggy (Graham Wagg) would have gone on to a bigger score, it needed one of us to get a hundred and it wasn't ideal to leave Owen Morgan not-out given the form he's in.
"It's a different game for me batting down the order after opening, you do appreciate the older ball!"
Sussex assistant coach Jon Lewis told BBC Sussex:
"It was a very good day, we bowled nicely in the morning to pick up five wickets before lunch though a perfect day would have been (Glamorgan all out) 180.
"I think the wicket's flattened out in the sunshine, so if we can get level by midway through (day two) then kick on, we'll be in a very strong position.
"Jofra's a very good bowler with the added advantage that no-one's really seen him, he seams the ball and he's got a great deal of pace, so all the attributes for a very promising young fast bowler.
"Ed Joyce is relentless, extremely professional, works diligently, he's very knowledgeable and a fine player- I'm sure there's a lot more runs to come from him for Sussex."