Sir Alex Ferguson fought Turkish police during a tunnel fracas in 1993, according to former skipper Steve Bruce.
Manchester United were eliminated from the Champions League by Galatasaray with the clash marred by a bust-up in the tunnel between players and Istanbul riot police.
Eric Cantona also saw red and the Frenchman was assaulted by a riot officer as they headed down the tunnel - leading to a furious reaction from United's players.
And Hull boss Steve Bruce has revealed Ferguson's role in the melee, reports the Manchester Evening News.
"We're all getting battered. Bryan Robson, captain of England, he's in there. Typical Bryan, he's swung this punch and there's a hook on the wall. Nowhere near the fella he's trying to hit, but he's caught his elbow on it, ripped his arm completely open. Blood everywhere. He's screaming, and a big Turk comes in and boots him," Bruce told the Mail.
"So now we're tearing into them, trying to fight our way out of there, and over my shoulder I see Fergie come flying back down the stairs. He's taking his jacket off as he comes. He's over 50 years old, but he's straight in, wades in. We eventually get back to the dressing room.
"Fergie comes barging through. His hair's all over the place, his tie is under his ear and he says, 'None of you have been fighting have you? No team of mine has been fighting, eh?' And we're all, 'No, boss'. So he says, 'Didn't think so', and goes out and tells the world that his players have been assaulted in the tunnel. And I remember the door closed behind him that night, and we all looked at each other and said: 'He'll do'. He created that spirit."
Ferguson vowed he would 'never go back', however United were drawn against Galatasaray in the 1994 Champions League group stages.