Worcestershire came up against an aggressive Matt Machan on the opening morning of the LV = County Championship clash with Sussex at Hove.
Paceman Charlie Morris made an early breakthrough in dismissing Luke Wells after Sussex skipper Ed Joyce had elected to bat.
But it was Worcestershire's sole success before lunch as the recalled Machan, who played in all six of Scotland's World Cup matches, helped Sussex to reach 153-1.
Machan's first 52 runs came off 27 balls with seven fours and two sixes – both of which sailed over the short pavilion side boundary and out of the ground.
Gareth Andrew took the new ball and began with a testing maiden to Joyce.
Luke Wells collected the first runs of the innings with a straight drive for four in the first over from Charlie Morris.
But Morris had his revenge when Wells, playing away from his body, was caught in the gulley by Tom Kohler-Cadmore off Morris when on nine and the total 16-1 in the sixth over.
Wells failed to add to his score after being dropped in the previous over from Gareth Andrew by Tom Fell at third slip.
Joyce survived one confident lbw shout from Andrew who then conceded three fours in an over to Machan on a good pitch.
Machan finished the session on 87 not out from 63 balls with 12 fours and three sixes in an unbroken second wicket stand of 137 with Joyce who was unbeaten on 44.
Jack Shantry made a second breakthrough in the third over after lunch.
Joyce on 49 flashed at a delivery from Shantry and Alex Gidman at first slip held onto a sharp chance with the score 161-2 in the 34th over.
Joyce and Machan added 145 in 27.4 overs for the second wicket.
Middle order batsman Alexei Kervezee was recalled to the Worcestershire side.
Kervezee replaced Moeen Ali – now on England duty in the West Indies – in the only change from the side beaten by 10 wickets by Yorkshire at New Road.
The Dutch international scored more than 800 Championship runs last season – second only to skipper Daryl Mitchell.
Sussex made two changes with Chris Nash (torn hamstring) and the unwell Michael Yardy replaced by Matt Machan and Ashar Zaidi respectively.
Sussex: LWP Wells, EC Joyce*, Craig Cachopa, MW Machan, LJ Wright, Ashar Zaidi, BC Brown†, A Shahzad, SJ Magoffin, TS Mills, ME Hobden
Worcestershire: DKH Mitchell*, RK Oliver, TC Fell, APR Gidman, T Kohler-Cadmore, AN Kervezee, OB Cox†, GM Andrew, JD Shantry, SMSM Senanayake, CAJ Morris