Kashif Ali hit an excellent half century and Nathan Smith picked up six wickets as 23 wickets fell on the first day of the Vitality County Championship match with Durham at the Seat Unique Rivverside.
Durham were initially bowled out for 190 as the Worcestershire attack exploited the bowler-friendly conditions and a green pitch after acting captain Jake Libby won the toss.
Smith was responsible for four of those wickets and there were three for on loan Ben Allison, two for Matthew Waite and one for Tom Taylor.
Worcestershire found batting an even bigger challenge and they were bowled out for 112 despite Kashif’s 55 with Ben Raine, Matthew Potts and Peter Siddle doing the damage for Durham.
But Smith struck back with two more wickets late in the day to take his tally this season to 25 as Durham closed on 33-3 – a lead of 111.
Worcestershire made two changes from the side which took on Surrey at Visit Worcestershire New Road.
Smith returned after being rested against Surrey in place of the injured Adam Finch. On loan Surrey spinner Amar Virdi replaced Shoaib Bashir who had returned to Somerset after a month on loan at New Road.
Club Captain Brett D’Oliveira was again ruled out with a shoulder injury and Jake Libby captained the side and put Durham into bat.
Smith got Worcestershire off to the perfect start by striking in the first over with the wicket of Durham captain Scott Borthwick. Borthwick (0) was undone by a delivery of full length which came back in and was lbw.
Fellow opener Alex Lees then survived a confident lbw shout from the New Zealander who quickly settled into a probing line and length.
Taylor shared the new ball and he was also soon amongst the wickets. Colin Ackermann (1) pushed forward to a ball of full length and keeper Gareth Roderick held onto a fine low catch.
New batter David Bedingham played some attacking strokes from the start but was also fortunate to play and miss at Smith three times in an over.
Taylor also went past the outside edge of the Australian twice in an over but it was Ben Allison who picked up his prized wicket in his first over after replacing Smith.
Bedingham (21) misjudged a delivery angled back into him and was bowled after offering no stroke with the total 39-3 in the 11th over to clinch a first bowling bonus point for Worcestershire.
There was more joy for Worcestershire in Matthew Waite’s opening over. Lees (17) hit a couple of boundaries but then pushed forward to Waite and Adam Hose held onto a sharp low catch at first slip.
Durham batted aggressively despite the steady stream of early wickets with Ollie Robinson powerful through the off side and Ben Stokes typically attacking as the 100 came up in the 25th over.
But Smith returned to strike a crucial blow on the stroke of lunch as he bowled Robinson for 35 with a gem of a delivery which came back in between bat and pad and dislodged the middle stump.
The lights came on for the afternoon session under gloomy skies and Stokes survived a confident shout for lbw from Taylor to the first ball after the resumption.
The England Test captain opted to go on the offensive and completed a 73 balls half century with 10 fours but his dismissal led to Durham losing their last five wickets for 30 runs.
Allison brought about his downfall on 56 when he went to pull a shorter delivery and only feathered through to Roderick. Bas de Leede (0) fell in the same over to the Roderick-Allison combination after attempting a drive.
Waite then angled a delivery across Ben Raine (3) and the left hander provided Roderick with another catch. Graham Clarke (28) went lbw to Smith after working to leg and the New Zealander clipped Matthew Potts off stump (11) as Durham were bowled out in 48.3 overs.
Smith finished with 4-36, Allison 3-57, Waite 2-43 and Taylor 1-45.
When Worcestershire began their reply, Roderick straight drove Raine for four but was then lbw on nine to a full and straight delivery from Potts.
Kashif looked in a aggressive form, leg glancing and hitting Potts through mid wicket for boundaries and cover driving Raine to the ropes.
Libby (13) was caught at third slip off Stokes just after becoming the first Worcestershire player to reach 500 first class runs this season.
Kashif Ali followed him to that milestone and there was time for Jones to hit three boundaries before a short break for bad light and rain.
When the players returned a successful of wickets fell. Jones (15) tried to turn on the leg side and edged Peter Siddle to third slip and Adam Hose (0) then lost his off stump to an excellent ball from the veteran Australian bowler.
Kashif cover drove and pulled Stokes for boundaries but a double bowling change brought more success for the home side.
Ethan Brookes (8) was lbw to Raine and Waite (0) lost his off stump to Potts. Smith (1) came down the wicket to Raine but only succeeded in slicing a catch to backward point.
Potts struck twice in two balls as Taylor nicked an away swinger and was caught behind and Allison (0) had his stumps shattered by Potts.
Kashif brought his half century up in spectacular fashion with six over mid wicket off Raine. But after appearing to suffer an injury to a calf, Kashif’s excellent knock ended when he lofted Raine to mid off.
When Durham batted for a second time, Smith was again amongst the wickets as Lees fell to a good catch by Brookes at third slip and Borthwick edged a lifter to Jones at second slip.
It became 27-3 when Clark was lbw to Taylor.
Worcestershire Head Coach, Alan Richardson, said: “The scores have reflected what the wicket was like. It feels as though there’s a ball out there with a wicket on it if you bowl in the right areas enough.
“The game has certainly moved forward quite quickly today. I think we bowled pretty well throughout and held our catches.
“Ben Stokes played well and put the pressure back on our bowlers, but we held our lengths pretty well. Everyone bowled well and Nathan Smith has been a standout performer for most of the season.
“He hasn’t quite always got the wickets he has deserved so it was nice for him to get those four in the first innings.
“We tried to get close to parity and make it a one-innings game, but they bowled really well and we lost five wickets for three runs. It was disappointing that we didn’t stop that momentum.
“The boys applied themselves well in the second innings with the ball. It was nice to get the inroads and hopefully we can keep chipping away.”