Worcestershire paceman Jack Shantry reached the 50 wicket mark for the season in the LV = County Championship but a fine innings from Luke Wright helped Sussex into the ascendancy on day two of the Division One match at New Road.
Shantry emulated Joe Leach in reaching the milestone – the second season in a row he has clocked up a half century of LV = CC victims.
It followed on from Alex Gidman completing an excellent fifty to earn Worcestershire a batting point after they had resumed on 185-9 from 70 overs.
But Wright batted with great fluency to reach 98 not out and Sussex reached 251-3 in reply – a lead of 41 – before bad light intervened.
Wright has added 157 in 34 overs with Ben Brown who is 45 not out.
Gidman, who remained unbeaten on 60, and Charlie Morris added 31 for the final wicket before the latter was bowled by Luke Wells.
Gidman pulled and square cut Chris Jordan for four and a single off the same bowler took Worcestershire to 200.
The former Gloucestershire batsman collected two more boundaries at Wells' expense before the innings came to an end.
When Sussex started their reply, Wells had a let-off on three when dropped at first slip off Joe Leach with only nine runs on the board.
Shantry shared the new ball with Leach and claimed his 50th Championship wicket of the season when he dismissed Sussex opener Michael Yardy (13).
He fell to a superb catch by Tom Fell diving away to his right at leg slip. It became 35-2 when Wells (10) edged through to keeper Ben Cox.
Chris Nash was also dropped – on 12 – in the slips in the final over before lunch from Shantry.
Charlie Morris accounted for Matt Machan (35) who perished to Fell at silly mid off to make Sussex 81-3 and then Nash was forced to retire on 38 with slight concussion after top edging a pull from the same bowler onto his helmet.
But Wright immediately looked in good touch although it took him 23 deliveries to get off the mark.
He produced a series of splendid strokes to bring up his 50 from 81 balls with nine boundaries and completed 1,000 Championship runs for the season in the first over after tea.
The players left the field because of bad light with Sussex 224-3 and 16 overs were lost before play resumed at 5.45pm for what turned out to be another five overs.