Leicestershire 251 and 144 for 3 (Rahane 47*) trail Glamorgan 550 for 9 dec (Ingram 257*, Holland 4-96) by 155 runs
Leicestershire's international pair Ajinkya Rahane and Peter Handscomb battled hard to give their side a chance of saving the game, after Glamorgan's Colin Ingram had continued his batting masterclass.
Rahane was 47 not out and Handscomb unbeaten on 33, Leicestershire 144 for 3, trailing by 155, when bad light stopped play with 21.2 scheduled overs remaining.
Both the Indian and Australian were dropped by Glamorgan legspinner Mason Crane, two of his three dropped catches coming off his own bowling, in moments which may come back to haunt the home side as they chase victory on the final day.
That was after Glamorgan had declared on 550 for 9, with a lead of 299, Ingram unbeaten on a personal best 257, Crane getting his day off to a better start with 49 runs to his name.
Glamorgan started the day in a strong position and soon set about building on those solid foundations, with Colin Ingram carrying on as he had done over the previous two days.
Having already notched his first ever double century, the fastest Glamorgan player to 1,000 runs in a season, he notched his first ever 250, confidently progressing in serene fashion.
He had good support from Crane who was one short of a well deserved half century when he was dismissed in one of the most unfortunate ways possible.
Ingram hit the ball firmly back down the ground, bowler Rehan Ahmed got a fingertip to the ball which went on to hit the stumps at the bowler's end before Crane could regain his ground.
New Zealander Fraser Sheat hit a breezy 34 while Ingram mainly watched on, Ned Leonard had one nice boundary before the declaration came just before lunch with Glamorgan nine down, 299 runs ahead on the first innings scores.
Ingram was 257 not out, having been on the field for all but one ball of the match, batting just three minutes short of ten hours, as Glamorgan added 119 runs to their total during the morning.
Leicestershire had a mountain to climb when they came out to bat, with their opening bowler, Ian Holland, also opening the batting.
Both sides needed patience and Rishi Patel and Holland withstood an impressive opening salvo from Timm van der Gugten and Fraser Sheat.
It was Dan Douthwaite who made the breakthrough, nipping one back to trap Patel LBW. Ned Leonard got the ball to nip back even more sharply to bowl Leicestershire captain Lewis Hill.
Van der Gugten got in on the act with one which lifted outside off stump and Holland tamely lobbed it to point where Billy Root to the catch.
That brought Indian Ajinkya Rahane and Australian Peter Handscomb together, who were always likely to form the nub of the resistance.
Glamorgan had their chances as Rahane gave two caught and bowled opportunities to Mason Crane when on 32, but the leg spinner put them both down, the first low to his left and the second sharp to his right.
Handscomb was on 26 when he pulled Sheat firmly in the air to midwicket where once again it was the unfortunate Crane who spilled the chance.
There was confusion over bad light at the end of the day, but the early finish was inevitable after the umpires tried to come back on for 10 balls only to be forced to call events off in the growing gloom.
