Murray Goodwin's half-century put Glamorgan in a dominant position on the second day against Lancashire at Colwyn Bay.
The former Sussex batsman made 69 as Glamorgan reached 242 all out - a first-innings lead of 119 in their Division Two clash.
Lancashire were then reduced to 49 for three before Ashwell Prince and Simon Katich put on 52 for the fourth wicket. However, in the penultimate over Prince went lbw shouldering arms to give Australian Michael Hogan his third wicket.
That left Lancashire, who sent in night watchman James Anderson, struggling at 104 for four, a 15-run lead for Glamorgan.
It had been a good morning for Lancashire and slow left-armer Simon Kerrigan who took three of the four wickets to fall. Glamorgan had looked relatively comfortable as the overnight batsmen Goodwin and Jim Allenby took their side into a first-innings lead.
That was after Glamorgan had resumed their first innings on 113 for four - a deficit of 10 runs.
Kerrigan came into the attack and changed the complexion of the morning, taking two wickets in the space of three balls ending a 67 run partnership for the fifth wicket.
Kerrigan had Allenby caught at short mid-wicket four short of his 50, and followed that up by dismissing Mark Wallace for a second-ball duck, caught at short leg by Karl Brown. Before lunch John Glover was adjudged leg before to Kerrigan, who finished with figures of four for 48.
In the last over before lunch Dean Cosker went lbw to Kyle Hogg with Glamorgan 203 for eight - a lead of 80.
Goodwin began the afternoon by reaching his half-century from 110 balls before Hogan was caught by Karl Brown at backward point off Hogg. The Glamorgan innings came to an end with Goodwin dragging a ball from Hogg onto his stumps.
Staring down the barrel of a 119-run first-innings deficit, Lancashire lost their first wicket in the fifth over when Luke Proctor edged Hogan behind to leave the visitors nine for one.
Lancashire found themselves in trouble when they lost Paul Horton and Brown in the space of 20 balls after tea. Horton edged Mike Reed behind before Brown was bowled middle stump by Hogan.
At that stage Lancashire still trailed by 70 runs before Prince and Katich recovered the position until the South African perished to Hogan just before stumps.