LV= County Championship Division Two, New Road, Worcester (day two)
Worcestershire 284: D'Oliveira 74*, Van Beek 53 & 127-8 Libby 40, Azhar Ali 39; McIlroy 4-27
Glamorgan 170 (48 overs): Cooke 38; Van Beek 4-42, Pennington 4-43
Worcestershire (4 pts) lead Glamorgan (3 pts) by 241 runs with two second innings wickets standing
Eighteen wickets fell in the day at New Road as Worcestershire claimed a first innings lead of 114 over Glamorgan, but then crashed to 127-8 in their second innings.
Jamie McIlroy took a career-best 4-27 to threaten the Pears' dominance.
Glamorgan never got to grips with the Worcestershire seamers as they were shot out for 170.
Logan van Beek claimed a best county performance of 4-42 and Dillon Pennington 3-43 on a tricky surface.
Worcestershire are still ahead in the game, but Glamorgan's late fightback gave them some hope of repeating their final innings chase of 2022.
Both sets of seam bowlers enjoyed themselves, getting some help from the pitch with variable bounce and movement aided by poor batting.
At the start of an eventful day, Joe Leach put Glamorgan under immediate pressure as he dismissed Eddie Byrom and Zain Ul Hassan early on, while nightwatchman James Harris fell to Pennington for 17.
Despite Worcestershire dropping four chances in the first session, Glamorgan were unable to profit as Sam Northeast edged Pennington to slip for seven and Jake Libby claimed a second catch to get rid of Colin Ingram for 30, Van Beek taking his first Pears Championship wicket.
Kiran Carlson was dropped twice and hit on the helmet on his way to 24, but drove debutant Ben Allison to cover straight after lunch.
Billy Root and Chris Cooke (38) provided the best partnership of the innings, adding 62 for the seventh wicket as they played some attacking shots without ever seeming quite in control.
But Cooke's departure was the end as numbers nine, 10 and 11 all registered ducks with Van Beek and Pennington cleaning up the tail.
Gareth Roderick fell first ball to McIlroy in the Pears' second innings, but Jake Libby (40) and Azhar Ali (39) added 81 in relatively untroubled fashion as Glamorgan, without injured strike bowler Timm van der Gugten, toiled in the first half of a marathon 50-overs evening session.
McIlroy returned to make the breakthrough as he found the edge of both men's bats and then had Jack Haynes caught at slip for 10 to register career-best figures.
The slide became a collapse as Harris and Ul Hassan picked up two wickets apiece with seven wickets falling for 40 in a remarkable reversal of fortunes.
The middle-order efforts were not helped by Adam Hose (16) and previous hero Van Beek both being bowled without playing shots.
Brett D'Oliveira, the match's top scorer with his unbeaten 74 in the first innings, survived the closing overs alongside Leach.