Kilmarnock boss Steve Clarke says he faced "sectarian" abuse from the "dark ages" during his side's 5-0 Scottish Cup last-16 replay defeat by Rangers.
Clarke said he was assured that "we don't have that in the west of Scotland any more" when he was "approached by Rangers about taking the job" at Ibrox.
He added: "To call me a Fenian b******, where are we living? The dark ages?"
The Ayrshireman left St Mirren in 1987 to sign for Chelsea, returning to take over at Kilmarnock last October.
- Morelos nets four as Rangers run riot
- How rampant Morelos ravaged Kilmarnock
- Reaction & as it happened
"They are not allowed to call my assistant [Alex Dyer] a 'black b', but they can call me a Fenian b******. What are we doing in Scotland?" said an emotional Clarke, who was linked with Rangers last spring.
"I wake up every morning and thank Chelsea for taking me away from the west of Scotland because my children don't understand this.
"Thankfully when I go down there my children don't have to worry about this. It's lovely being back in the west of Scotland."
Kilmarnock captain Kris Boyd said he was subjected to sectarian abuse during Sunday's game with Celtic at Rugby Park.
'We have got a cancer and we need to stamp it out' - analysis
Former Scotland midfielder Michael Stewart on BBC Sportscene:
"Steve Clarke is a man of integrity and he shouldn't have to listen to it. But it is very difficult to police it because what happens if a whole stand is shouting sectarian abuse?
"If clubs are serious about stamping it out, for me strict liability is the only way we are going to get to the root cause of the issue. I know it is turkeys voting for Christmas but ultimately the prize is much bigger.
"This is a great country we have got here but we have got a cancer and we need to stamp it out."
David Scott, Campaign Director for anti-sectarian charity Nil by Mouth on Radio Scotland:
"It is difficult to combat if you don't throw a punch. Scottish football has failed for generations to tackle sectarian abuse.
"What we have seen, particularly - it has to be said - from the Old Firm clubs, is a complete washing of hands where they say 'this is nothing to do with us, this is society's problem, we can't solve it', where people think they can go to matches and behave in this manner.
"You would not behave like that in the workplace or in the community without sanction, so why do we allow this permissive environment? It is simply because the clubs and governing bodies don't have the backbone, the bottle, the spine to do something about it."
'The officials decided the game. It's embarrassing'
Four goals from Alfredo Morelos and another from Andy Halliday earned Rangers a quarter-final tie at Aberdeen.
However, all but one of those goals came after the controversial 25th-minute dismissal of Kilmarnock goalkeeper Daniel Bachmannn after his elbow struck the head of Glen Kamara while waiting for a corner.
Clarke described the red card as a "joke" and "embarrassing" and that we "might as well go home" if that is the standard of refereeing.
He also railed against Alan Muir's failure to award his side a second-minute penalty after Joe Worrall grappled with Eamonn Brophy.
"The officials decided the game. It's embarrassing," Clarke said. "If the penalty had been given in the first two minutes it would have been different.
"And the red card is a joke. The goalie just lifted his arms. Every goalie does it every week. It's embarrassing. If that's the standards we might as well go home.
"Why speak? It's every week. How can I talk about football tonight?"