Former Manchester United captain Roy Keane has revealed he once left team-mate Peter Schmeichel with a black eye following a pre-season brawl, in extracts from his autobiography released on Monday.

In the book, The Second Half, which is published on Thursday, the former Ireland midfielder also lifts the lid on his acrimonious departure from United in 2005 and criticises Rio Ferdinand over his missed drugs test.

Keane reveals that the alcohol-fuelled fight with former Denmark international Schmeichel, one of United's greatest ever goalkeepers, occurred during a pre-season trip to Hong Kong in 1998.

"There'd been a little bit of tension between us over the years, for football reasons," wrote Keane, in an excerpt from the book published on the website of British newspaper the Daily Mirror.

"Peter would come out shouting at players, and I felt sometimes he was playing up to the crowd: 'Look at me!'

"He was probably doing it for concentration levels, but I felt he did it too often, as if he was telling the crowd: 'Look what I have to deal with.'

"He said, 'I've had enough of you. It's time we sorted this out.' So I said, 'OK,' and we had a fight. It felt like 10 minutes. There was a lot of noise -- Peter's a big lad.

"I woke up the next morning. I kind of vaguely remembered the fight. My hand was really sore and one of my fingers was bent backwards."

He added: "Butty (Nicky Butt) had refereed the fight. Anyway, Peter had grabbed me, I'd head-butted him -- we'd been fighting for ages."

According to Keane, Schmeichel explained away his black eye at a subsequent press conference by claiming that one of his team-mates had accidentally elbowed him in training.

Keane left United in November 2005 after launching a withering attack on some of his team-mates during an interview with United's in-house television channel, MUTV, that was never broadcast.

In his book, he says that he learnt of United's desire for him to leave during a subsequent meeting with then manager Alex Ferguson.

"I said to Ferguson, 'Can I play for somebody else?'" writes Keane, who is now working as an assistant coach for Aston Villa and the Irish national team.

"And he said, 'Yeah you can, because we're tearing up your contract.' So I thought, 'All right -- I'll get fixed up.'

"I knew there'd be clubs in for me when the news got out. I said, 'Yeah, I think we have come to the end.'"

Keane joined Celtic soon after, before retiring in June 2006.

On the eight-month suspension that Ferdinand received in 2004 for missing a drugs test, Keane writes: "He suffered for it and so did the team.

"If it had been me, and the doctor had said I had to do a drugs test, I'd have gone and done it. It wasn't something I'd have forgotten."

Keane spent 12 years at United, eight as captain, and won seven Premier League titles, four FA Cups and the 1999 Champions League.