Worcestershire all-rounder Joe Leach was again amongst the wickets on the second morning of the LV = County Championship clash with Durham at New Road.
Leach has returned career best figures of 6-73 in the previous Championship match with Warwickshire at Edgbaston.
He continued in that vein by dismissing Durham openers Mark Stoneman and Keaton Jennings plus captain Paul Collingwood.
Charlie Morris and Jack Shantry maintained the pressure with two and one wickets respectively as Durham reached 73-6 off 35.2 overs by lunch in reply to Worcestersire's first innings total of 323 all out.
It was a testing morning for the Durham batsmen in similar conditions to those faced by Worcestershire yesterday after being put into bat.
Durham resumed on 14-0 and Jennings (12) played and missed twice at Leach before edging to Worcestershire skipper Daryl Mitchell who took a sharp low catch at second slip.
New batsman Borthwick edged Morris for four and Stoneman nicked a delivery from the same bowler just short of Alex Gidman at first slip.
Leach made the second breakthrough when Stoneman (14) went for an expansive drive and was bowled.
Collingwood made just three before he became Leach's third victim when adjudged lbw with Durham 47-3.
Leach was eventually rested after an excellent spell of 9-0-28-3 and replaced by Morris at the New Road end and he struck in his first over back into the attack.
Michael Richardson (5) drove at a delivery which left him and was caught behind by Ben Cox.
Jack Shantry settled into his normal immaculate line and length at the Diglis End as the score trickled along at barely two an over.
The left armer was eventually rewarded when Gordon Muchall (1) was adjudged lbw.
Then in the last over Calum MacLeod (3) tried to work Morris through mid wicket and was caught via an inside edge onto his pad by Richard Oliver at short leg.