Matt Prior and Mike Yardy both managed half centuries as Sussex hit 300-8 during the only day of play against champions Lancashire.
The visitors won the toss and chose to bat, with openers Paul Horton and Stephen Moore falling for 16 and 18 runs respectively.
Steven Croft was dismissed for 27, with Lancashire on 112-4. Four runs later, top scorer Karl Brown was run out on 41 and Gareth Cross followed, having added just 2 runs.
Naved Arif Gondal had a respectable 3-34 by the time Lancashire declared on 144-8.
Sussex openers Chris Nash and Ed Joyce scored 33 and 32 runs before both being bowled LBW by debutant Ajmal Shahzad, who claimed 3-71. His other wicket was Luke Wells, also LBW, for just 2 runs.
If Sussex looked shaky at 85-4, the fifth wicket stand of Yardy and Prior, which added 142, restored hope.
Prior hit four sixes and five fours and top scored with 86 while the skipper notched up 63.
Joe Gatting was next in and made 42 not out.
Sussex declared on 300-8 and ended the final day – the only day of play – with eight points to Lancashire’s five.