Glamorgan 359 (van der Gugten 50) and 106 for 4 lead Leicestershire 132 (Wagg 3-25) by 333 runs
Glamorgan have not won a Championship game at their Sophia Gardens headquarters since Leicestershire were beaten three years ago, but they are on course to repeat that success sometime during the final two days of what has been a desperately disappointing season.
After 200 supporters had attended a members forum on Monday, when the club announced there would be an independent external review conducted in October, the players responded with a satisfying all-round performance to end the second day in a commanding position.
After gaining a first innings lead of 227, Michael Hogan opted not to enforce the follow on. With two-and-a-half days remaining, Glamorgan's batsmen, who have been short of runs for most of the summer, took the opportunity for some late-season practice.
They took Glamorgan's lead on to 333, Chris Cooke contributing an unbeaten 41, and they are likely to bat for another session on Wednesday. The visitors will then need to show far more dedication and application than they did in the first innings when they were dismissed for 132 in only 48.3 overs.
When play resumed on the second morning, the ninth-wicket pair of Timm van der Gugten and Kieiran Bull extended their partnership to 80, with Glamorgan gaining four batting points, the most in an innings this season. Van der Gugten reaching his second half-century in three games.
Leicestershire lost Sam Evans in Hogan's opening over, then the innings began to slide as Colin Ackerman was out to Graham Wagg in the final over before lunch and Mark Cosgrove to the first ball after the interval. Apart from Harry Dearden, who scored 48 from 87 balls with ten fours, no other batsman could cope with an accurate Glamorgan attack, Wagg ending with figures of 10-4-25-3.
Stephen Cook,signed by Glamorgan for the final four games, failed again when he was leg before to Tom Taylor for 5 - the South African ending his short stay with only 120 runs from eight innings and a paltry average of 15.00.
Glamorgan then wobbled, as three wickets fell for one run. Nick Selman ended a poor season when he was lbw to Dieter Klein, who then had Jack Murphy caught behind, and when Carlson wafted at a wide one from Gavin Griffiths, the home team had stumbled to 39 for 4.
They recovered as Cooke and Jeremy Lawlor shared an unbeaten partnership of 67 for the fifth wicket, to leave their team in control on 106 for 4.