Promotion-chasing Sussex had the better of an eventful opening day at The Pattonair County Ground, despite two wickets for Luis Reece in the evening session.
Batting first, Anuj Dal top-scored with 35 in a mark of lower-order resistance, while David Wiese claimed 4-18 to compliment early wickets for the Sussex pace attack.
The visitors enjoyed the better of the conditions to reach 116-3 at the close, trailing by 22 after Reece (2-27) and Fynn Hudson-Prentice (1-29) struck early.
After play way delayed until midday, an uncontested toss saw Derbyshire put into bat in overcast conditions which were capitalised on by the pacey Ollie Robinson and the experienced Chris Jordan.
Reece (0) was out in the second over, while Billy Godleman (22) fell shortly before lunch, caught by Salt off Topley, leaving Derbyshire 43-2 at the interval.
Wayne Madsen resumed, but was caught by George Garton off Jordan in the first over after lunch, while Harvey Hosein (7) was bowled by Wiese soon after.
Wiese continued and had Matt Critchley (0) caught by Delray Rawlins, before he bowled Mattie McKiernan (0) with the next delivery.
Leus du Plooy was undone by a full, moving delivery, chipping to Phil Salt off Topley after getting himself set with 24.
Batting with the tail, Dal counter-attacked to take Derbyshire into three figures, with the all-rounder frustrating Sussex’s bowlers for 51 balls before being caught by Ben Brown off Wiese to end the Derbyshire innings on 138.
Responding well with the ball, Reece opened from the City End and had Salt (3) caught by Critchley off a top-edge, before he bowled Wells (5), clipping the bails with a swinging delivery.
With the dangerous openers gone and Will Beer lbw to Hudson-Prentice’s first ball, Derbyshire had the travelling side 25-3, still trailing by 113.
But an accomplished knock from South African batsman Stiaan van Zyl (49 not out), who was ably supported by Delray Rawlins (26 not out), took Sussex to 116-3 at the close, handily placed trailing by 22 runs heading into Day Two.
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