A FIRST century of the season from captain Mark Wallace put Glamorgan in with a good chance of winning their first LV= County Championship Division Two match going into the final day against Leicestershire at Cardiff.
Wallace's 118, from 150 balls with 12 fours, followed up Marcus North's hundred on day two and was the backbone of Glamorgan's late middle order as the Welsh county declared their first innings on 558 for nine - a lead of 287.
Leicestershire battled back effectively in the final session to close on 84 for one in their second innings, although still trailing by 203.
The visitors lost Greg Smith early on caught behind from a good James Harris ball to be reduced to 11 for one in the eighth over.
But Michael Thornely (36 not out) and Ned Eckersley (37no), Leicestershire's top scorers from the first innings, took their side through to stumps without any further scares.
Earlier, Glamorgan, who resumed on 302 for five - a lead of 31, enjoyed a productive morning session with 124 runs coming very easily.
The home side's only blemish was the loss of nightwatchman Dean Cosker who was lbw to Wayne White in the fourth over of the day.
After that, despite Leicestershire taking the second new ball, Wallace and Jim Allenby completely dominated in reaching their first half-centuries of the season during a partnership worth 139 for the seventh wicket.
Wallace was in sparkling form going to his 50 from 76 balls with five fours, while Allenby followed him just before the lunch interval bringing up the landmark from 102 balls with a six over mid-wicket.
It was the first time Glamorgan have celebrated maximum batting points this season with Leicestershire skipper Ramnaresh Sarwan using nine bowlers.
Glamorgan reached lunch in a healthy position at 425 for six.
And an already decent lead was extended after the interval despite the seventh-wicket stand coming to an end when Allenby was trapped leg before to White. Allenby went for 61 from 128 balls.
But Glamorgan's momentum continued as Wallace and Harris put on 96 in only 16.4 overs as they further strengthened their position.
Harris fell, caught behind down the leg-side off Claude Henderson, two short of his half-century before Wallace holed out to extra cover off the same bowler with Glamorgan declaring 3.4 overs later.