Fans clashed on the Ibrox pitch after Celtic knocked Rangers out of the Scottish Cup on penalties.
The Hoops progressed to the semifinals despite failing to register a single shot on target in 120 minutes of action.
Celtic secured a 4-2 shoot-out victory after the goalless draw before dozens of their fans invaded the pitch. That sparked an invasion from hundreds of Rangers supporters and missiles were thrown as police and stewards moved to form a barrier.
Flares were thrown and some minor skirmishes appeared to take place before order was restored and the 7,500 Celtic fans were left to celebrate alone.
Rangers captain James Tavernier hit the bar with the first penalty before fellow substitute Djeidi Gassama blazed over, with Tomas Cvancara then sealing the victory and prompting the chaos.
Celtic striker Daizen Maeda had a goal disallowed for offside following a VAR review, but Martin O’Neill’s side otherwise never threatened.
Statistics showed that Rangers managed 24 shots and they also had a goal wiped out by VAR following an obvious handball by Emmanuel Fernandez.
But the hosts struggled to seriously test Viljami Sinisalo and were denied on a number of occasions by some penalty-box blocks.
The post match clashes have been branded a “disgrace” and “an embarrassment for Scottish football” by the Scottish Football Association.
An investigation has also been launched.
A statement read: “The Scottish FA condemns the behaviour from supporters entering the field of play following today’s Scottish Gas Scottish Cup quarterfinal at Ibrox Stadium.
“An investigation will be carried out immediately in line with the Judicial Panel Protocol.”
Former Scotland international Charlie Adam, speaking on talkSPORT, said: “It’s a disgrace.
“It’s a sad day for Scottish football. For the Old Firm that we talk about being our leadership teams and [what] they represent, it’s an embarrassment for our game.
“And as a national team we’re trying to improve and we’re trying to get better. But these two clubs have let us down as a nation and they have to have a look at themselves today.
“Both football clubs have to look at themselves because they are the standard-bearers for us as football clubs and they have, both [sets of] supporters have let themselves down.
“It’s an embarrassment for Scottish football.
“This should not be happening. In this day and age this should not be happening and we have to get control of it quickly because if it doesn’t it’ll keep escalating and escalating and there’ll be big, big problems.”
