James Kirtley's four wickets and three more from Ollie Rayner helped Sussex bowl out Sri Lanka A for 225 on the first day at Hove.
Choosing to bat, Sri Lanka A had an early setback when they lost Michael Vandort to Kirtley for 4 before a stabilising second-wicket stand of 76 between Mahela Udawatte and Malinda Warnapura levelled the balance.
Both fell in quick succession to Kirtley, however, and Sri Lanka's middle-order struggled against Rayner and Chris Liddle, though the wicketkeeper Kaushal Silva did crunch five fours in an unbeaten 49 to edge his side past 200 and into a position of relative respectability.
Sussex, in reply, got off to a brisk start with Richard Montgomerie and Carl Hopkinson taking particular liking to Chanaka Welegedara. And although Akalanka Ganegama bowled Hopkinson for 21, Sussex had hustled to 78 for 1 at stumps, trailing by 147.