Gordon Strachan says "yob behaviour" in football is "nothing new" after opening up on being targeted during his career.
As an Aberdeen player Strachan was attacked by a Celtic fan in 1980 and he says he and his family were verbally abused during his time as Celtic boss.
Aston Villa's Jack Grealish was punched by a supporter and Rangers' James Tavernier confronted by a Hibernian fan earlier this month.
"It was happening years ago," said the former Scotland boss.
"The warnings were coming for this because we have allowed yob behaviour to fester in stadiums over the last 15 to 20 years.
"There used to be hooligan behaviour where all the nutcases went to one corner to shout their bile. You knew where they were.
"But it's seeping through to all parts of the ground now."
Birmingham City supporter Paul Mitchell invaded the pitch in Sunday's Championship fixture between his club and Villa before striking Villa captain Grealish from behind.
Mitchell was jailed for 14 weeks on Monday after admitting assault and encroachment on the pitch.
"It happened to me about 30-odd years ago at Celtic Park when a fan ran on during the game," Strachan told BBC Radio 5 live.
"When I turned around on the end of my finger was a fan. He decided to crack me around the head.
"I saw him about 30 seconds previous. The police were trying to take him out of the crowd because he had a bottle in his hand.
"I got away with that one but it did spook me for the rest of the game. I think Jack would have found it hard. It's ironic he went on to score the winner, which is justice really."
'The bile, there was spit coming out of their mouths'
Strachan also recalled two incidents where, as Celtic manager, he complained to police about treatment from supporters.
"I said to the police, 'you can see these guys' and they were horrendous. The bile, there was spit coming out of their mouths," he explained.
"I said to the commanding officer if he was going to do anything. 'Just watch the game' he said."
England manager Gareth Southgate described Manchester City's Raheem Sterling, who suffered alleged racial abuse from Chelsea fans in December, as an "outstanding role model".
And Strachan added: "We have allowed this to fester to the point young Raheem Sterling has decided enough is enough.
"If we had done something 15 years ago, 10 years ago, we'd never have got to the stage."