Jeevan Mendis and Shiv Thakor took the wickets for Derbyshire, but Worcestershire made the most of improving conditions on Day Three at The 3aaa County Ground.
Due to rain affected first two days, 104 overs were possible on Day Three. Derbyshire added 75 first-innings runs in the morning session, including a 45-run partnership between Tony Palladino and Tom Taylor, taking them to 275 all out.
Daryl Mitchell and Brett D’Oliveira put on 243 for the opening wicket but wickets from Thakor and Mendis pegged the visitors back, Worcestershire closing on 323-3.
Billy Godleman said: “The wicket definitely played slightly differently when they batted, there was less in it for our bowlers but we were disappointed with how we bowled with the new ball although both openers played well.
“I imagine they will come out and play a few shots and then we will have an opportunity and challenge against their bowlers in the second innings but we will be doing everything we can as a team to fight as hard as we can.”
Mendis hit Nathan Lyon for six down the ground in the fifth over of the morning, before Daryn Smit (33) was out to Joe Leach in the following over, caught in the slips by Daryl Mitchell.
After striking two fours and one six, Mendis followed soon after, caught at deep square leg by Tom Fell off Leach for 19.
Taylor and Palladino’s 45-run ninth wicket partnership took Derbyshire past 250, before Taylor feathered one through to Ben Cox off Ed Barnard for 17.
The innings came to a close when Palladino was out lbw to Barnard for 32, Derbyshire reaching 275 all out.
Leading the Worcestershire reply, Mitchell and D’Oliveira survived the five overs before lunch and began to accumulate runs in the second session.
The pair brought the 100 partnership up in the 20th over as they both reached half-centuries.
Thakor bowled tightly early on, conceding just ten runs in his five overs before tea as Derbyshire looked for the breakthrough.
Shortly after the tea interval, Mitchell reached his century off 128 balls, including 11 fours and one six. He was followed by D’Oliveira, who reached the milestone off 160 balls, with 11 fours.
After two good spells of bowling, it was Thakor who ended the 243-run opening stand, Mitchell out lbw for 120.
Mendis picked up his first wicket of the match in the 66th over, new batsman Tom Fell playing onto his stumps, bowled for 13.
D’Oliveira reached 150 before he was caught and bowled by Mendis without adding to his score, with Worcestershire set to resume on the final day on 323-3.
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