Glamorgan 199 and 11 for 1 need a further 170 runs to beat Leicestershire 96 and 283 (Dexter 73, Robson 72, van der Gugten 4-81)
Glamorgan's seamers picked up Leicestershire's last eight second-innings wickets for just 85 runs to put the visitors in a strong position to go on and win their Division Two Specsavers County Championship match at Grace Road.
Needing 181 to win, Glamorgan did lose an early wicket, pacy left-arm seamer Dieter Klein trapping Nick Selman lbw for just 2 before bad light saw play ended 15 overs early.
The morning had seen Leicestershire openers Angus Robson and Paul Horton extend their second-innings partnership to 123 before being parted. Robson hit three fours in a single over from Timm Van der Gugten to bring up his ninth half-century of the season before Horton was drawn into pushing at a Craig Meschede delivery and edged to second slip.
On the same score, Robson attempted to cut a short ball from Lukas Carey but succeeded only in edging to first slip, where Will Bragg held the catch.
Neil Dexter and Mark Cosgrove added 75 for the third wicket before the lCosgrove, having survived two vehement appeals for catches behind the wicket, drove airily at a Meschede inswinger delivered from around the wicket and had his off stump knocked back.
Ned Eckersley played two glorious back-foot drives through the off side before clipping a Michael Hogan leg-stump half-volley straight into the hands of square leg, and Mark Pettini, having suffered a first-ball duck in the first innings, had made only 1 when he chopped a wide delivery from Van der Gugten on to his stumps.
Harry Dearden, making his home debut for Leicestershire, played solidly in going to 16 before being trapped leg before on the back foot to a van der Gugten inswinger, and the tail quickly followed, with Hogan picking up two wickets in two balls. Dexter was the last man to go, looking to force a wide delivery into the off side and like Pettini, edging the ball into his stumps, to give van der Gugten match figures of 9 for 133.
Klien's dismissal of Selman indicated Glamorgan might not find their target easy to reach, but with the ball continuing to swing Leicestershire were frustrated when light forced an early close.