Club Captain Brett D’Oliveira helped inspire a Worcestershire comeback on his return from injury for the LV=Insurance County Championship top three encounter with Glamorgan at New Road.
D’Oliveira, sidelined for three weeks with a dislocated shoulder, came to the wicket with Worcestershire 103-5 after they had been put into bat.
He top-scored with 74 not out and was given excellent support by Logan van Beek, who was making his Championship debut and on loan Essex all-rounder Ben Allison in partnerships of 101 and 64.
Earlier, Gareth Roderick and Adam Hose had led a partial recovery in challenging conditions during the morning session from 33-3.
It enabled Worcestershire to secure two valuable batting bonus points before they were dismissed for 284 and then Glamorgan closed on 3-0.
Worcestershire handed a debut to Allison after injuries to Matthew Waite and Adam Finch led to a search for a temporary replacement.
The Glamorgan new ball pair of Tim van der Gugten and Jamie McIlroy made early breakthroughs on a pitch offering enough assistance to encourage the seamers.
Jake Libby (6) has experienced a prolific summer with more than 900 Championship runs but the opener tried to force van der Gugten off the back foot and was caught behind.
Roderick off drove van der Gugten for the first boundary but Azhar Ali (3) clipped McIlroy straight to mid wicket.
Jack Haynes, playing his first senior game for six weeks after injury, was undone by a delivery from James Harris which nipped away and was caught behind.
Roderick passed 600 runs for the summer but survived a low chance to second slip on 23 off former Worcestershire Academy player Zain Ul Hassan.
He battled away in typically resolute fashion through to lunch with Hose who had returned to the side after his spell with Northern Superchargers in The Hundred.
Roderick (43) added only a single after the resumption before he was lbw after pushing forward to Harris.
Kashif Ali (9), the leading six hitter in the Metro Bank One Day Cup with 21 maximums, could only pick out mid wicket off McIlroy.
Hose had batted impressively in mixing defence with aggression but on 43 tried to cut a widish delivery from McIlroy and only found first slip.
D’Oliveira and van Beek joined forces and redressed the balance during an aggressive stand.
Van Beek, who played for Worcestershire in the Metro Bank One Day Cup, mixed some powerful hitting with watchful defence while D’Oliveira again demonstrated his liking for facing Glamorgan.
He has struck three centuries, including a career best 202 not out, against them in addition to registering his best bowling analysis of 7-92.
Van Beek cover drove Ben Kellaway for his 10th four to complete a 73 ball half century and also earn Worcestershire their first batting point.
The partnership was broken shortly after tea when van Beek (53) attempted to drive ul Hassan and was caught and bowled low down.
But D’Oliveira completed his own fifty from 87 deliveries, also at Kellaway’s expense with a late cut for his seventh boundary, and Allison gave him good support.
They added 64 in 18 overs before Allison (37) aimed a drive at Harris and was bowled via the inside edge and then Joe Leach (1) and Dillon Pennington (5) fell in quick succession to Ul Hassan