Worcestershire gained the upper hand after claiming four wickets during the post tea session on the second day of the LV = County Championship match with Glamorgan at New Road.
Tom Kohler-Cadmore had achieved his career best score – 85 – for the second successive innings in helping Worcestershire total 352 all out in their first innings.
Then Saeed Ajmal picked up two wickets and ran out Glamorgan dangerman Jacques Rudolph when he looked set for a third successive Championship century as the visitors closed on 222-6 from 75 overs.
Nineteen-year-old Kohler-Cadmore had registered his maiden Championship half century when making 56 in the previous match with Leicestershire at Grace Road.
Academy product Kohler-Cadmore struck 10 fours and a six and faced 183 deliveries during his 252 minute stay at the wicket.
Worcestershire resumed on 266-5 with Kohler-Cadmore on 60 and nightwatchman Jack Shantry on five.
The pair scored freely in the early stages with Kohler-Cadmore gaining two boundaries off Rory Smith via a thick edge to third man and a handsome cover-drive.
Shantry, who has chipped in all season with the bat, advanced to 17 via a square cut for four off Michael Hogan and a cover-drive for three at Smith's expense.
The pair added 32 before Shantry (17) fell to a fine low catch at fine leg by Tom Lancefield off Hogan with the total on 293.
Ben Cox was dropped on nought at first slip by Chris Cooke off Jim Allenby before the 300 and a third batting point in the 105th over.
The Worcestershire wicket-keeper made a rapid 17 with the aid of three fours before he pushed forward to Allenby and was bowled.
Kohler-Cadmore's fine knock ended five runs later when he was adjudged lbw to Smith.
But then Joe Leach and Ajmal added 30 useful runs for the ninth wicket before both were dismissed with the total on 352.
Leach (17) edged Allenby and was caught behind by Mark Wallace and Ajmal (14) went to sweep Dean Cosker's first ball and was given out lbw.
Hogan finished with 4-73 and Smith 3-98.
Glamorgan were left with 25 minutes batting before lunch and Morris broke through in his first over when Lancefield (1) fell to a fine low catch by Tom Fell at third slip.
Rudolph and Will Bragg dug in to add 75 in 33 overs during the afternoon session.
Bragg had defied Worcestershire throughout the final day of the meeting at the Swalec Stadium in making 91 not out off 92 overs.
But on this occasion after making 28, and surviving one stumping chance off Moeen Ali, he edged Ajmal to skipper Daryl Mitchell at slip.
Glamorgan were on 103-2 at tea but suffered a further setback to the first ball after the interval when Ben Wright, who had been dropped off Ajmal when on two, was adjudged lbw to Moeen Ali for nine.
It became 132-4 when Chris Cooke (12) played back to Ajmal and also was trapped lbw.
Jim Allenby decided on an initial aggressive approach and a six over square leg off Ajmal brought up the 150 in the 53rd over.
He out-scored Rudolph in a stand of 51 in 13 overs before Mitchell brought Joe Leach back into the attack – and in his first over he yorked Allenby for 34.
Rudolph looked set for a third successive Championship 100 despite having a runner for the majority of his innings.
But after making 88 the South African was run out by Ajmal's direct hit after turning Leach to mid-wicket to leave the visitors on 190-6.
Mark Wallace (33 not out) dominated an unbroken stand of 32 with Rory Smith (two not out) but Glamorgan still trail by 130.