|Glamorgan 309 & 57-6: Gohar 3-7|
|Gloucestershire 419: Dent 75, T Price 71, Van Buuren 65; Hogan 3-49|
|Glamorgan (5 points) trail Gloucestershire (6 points) by 53 runs with four second innings standing|
An astonishing spell from Pakistan spinner Zafar Gohar put Gloucestershire on the verge of victory as Glamorgan crashed to 57-6, still 53 behind.
Gohar took 3-7 in 10 overs in the evening session.
The visitors earned an unexpected lead of 110 on day three in Cardiff thanks to lower-order heroics led by Tom Price, with a career-best 71.
Gloucestershire are set for a seventh Championship win, while Glamorgan face a third straight loss.
The teams looked likely to be almost level on first innings when Gloucestershire were 310-8, despite useful middle-order runs from debutant wicket-keeper Ben Wells (40) and Ben Charlesworth, batting at seven after injury, with 44.
But Price patiently ground out valuable runs in a long afternoon session, aided by David Payne (34) and Jared Warner (10 not out).
Spinner Andrew Salter put the brakes on with 2-93 in a lengthy stint of 42 overs on a placid pitch.
Glamorgan started as if they wanted to knock off the deficit in double-quick time with 39 in seven overs before David Payne induced David Lloyd to edge to slip for 17.
Left-armer Gohar, brought on early, made up for an easy dropped catch with his first ball as Hamish Rutherford (17) cut to slip.
Gohar, who played one wicketless Test in January 2021, then had Nick Selman and Kiran Carlson both caught at slip without scoring.
Ryan Higgins bowled Eddie Byrom for eight, playing no shot, while Chris Cooke, on six, drove Graeme van Buuren to cover before bad light temporarily spared Glamorgan’s blushes after a dreadful collapse.
Meanwhile, there was no play in the other Division Two matches at Northampton and the Oval, or in any of the Division Three games at Derby, Leicester and Lord’s due to bad weather on Tuesday.