GLAMORGAN are battling in the second innings but Tom Kohler-Cadmore's fourth first-class century put Worcestershire in charge of the Specsavers County Championship Division Two clash at Cardiff.
Kohler-Cadmore struck 102 as Worcestershire made 403 for a first-innings lead of 196 before Glamorgan closed on 141 for three - still 55 runs adrift.
The home side's hopes of setting Worcestershire a challenging total to chase seem to rest with Colin Ingram, who looked in good touch in reaching the close unbeaten on 41.
Worcestershire resumed in the morning at 180 for four with Kohler-Cadmore and Ben Cox taking their fifth-wicket partnership to 116 before Cox was caught behind off Michael Hogan for 42.
Kohler-Cadmore rarely played a false stroke and when Lukas Carey overpitched he was struck for three successive fours through the off-side.
Ed Barnard survived a confident appeal for leg before early in his innings and Kohler-Cadmore should have been out on 95 but Nick Selman dropped a straightforward chance at cover.
Kohler-Cadmore went on to reach his century from 157 balls shortly afterwards, reaching the landmark by driving Michael Hogan to the boundary but the Australian got his revenge with the next ball when the batsman edged behind to give Chris Cooke his fifth catch of the innings.
Although Joe Leach went cheaply in the over before lunch, Barnard went on to reach his third championship fifty before falling leg before to Marchant de Lange for 59.
When Josh Tongue (six) was run out after a direct hit from Kieran Carlson, Worcestershire needed a further 29 runs for maximum batting bonus points, but John Hastings and Jack Shantry reached the target with ease, with Hastings reaching his half-century in his first innings for Worcestershire before he was last out for 51, holing out at deep mid-off.
Glamorgan began their second innings on a much more solid base than first time around as Jacques Rudolph and Nick Selman shared 74 for the first wicket.
Teenager Tongue claimed his first championship wicket to break the stand when he removed Rudolph for 29 after the Glamorgan skipper played over a full delivery.
Three balls later, Tongue accounted for Glamorgan's top-scorer in their first innings, David Lloyd, who was trapped in the crease and leg before for six.
Ingram, on a king pair, was untroubled from the start, playing some classy drives through the off-side and although he saw Selman removed by Hastings for 42, the South African left-hander remained until the close and will need to make a big contribution to give Glamorgan any hope of victory.