Murray Goodwin’s magnificent century put Glamorgan in a dominant position on day two against Leicestershire.
The 40-year-old’s fourth Championship hundred of the summer also took him past 1,000 runs for the season.
He hit 29 fours, but was eventually bowled for 178 by James Sykes after stands of 140 and 189 with Jim Allenby (76) and Mark Wallace (86).
All-rounder Ben Raine marked his first-class debut with 2-72, but Glamorgan closed on 445-7, a lead of 242.
Glamorgan had been in trouble at 24-3 on the opening day after bowling the visitors out for 203 and, when Raine struck to have Chris Cooke caught behind for 22, the prospect of a first-innings lead was still in the balance.
However, the inexperience of a Leicestershire attack in which the oldest member is only 24 was exposed by Goodwin.
He was at the crease for six hours and 40 minutes, facing 316 balls to help his side secure maximum batting points, as he plundered his 71st first-class century.