Alex Ferguson's Manchester United reign has been marked by colorful outbursts and putdowns. Here's a selection of some of his most memorable quotes.

Looking back on when he was hired by United in 1986: "My greatest challenge is not what's happening at the moment, my greatest challenge was knocking Liverpool right off their (expletive) perch. And you can print that." 

Liverpool won the last of its 18 English titles in 1990. Ferguson's United won 13 between 1993 and 2013 to take the team's total to a record 20.

On Manchester City emerging as United's rival in 2008 following the takeover by Abu Dhabi's Sheikh Mansour: "There has been a lot of expectation on Manchester City and with the spending they have done, they have to win something. Sometimes you have a noisy neighbor and have to live with it. You can't do anything about them."

City won the Premier League in 2012 but United regained the trophy last month.

On Arsenal manager Arsene Wenger, whose side won the Premier League three times during Ferguson's time at United: "They say he's an intelligent man, right? Speaks five languages. I've got a 15-year-old boy from the Ivory Coast who speaks five languages!"  

On the mind games employed by Italian teams: "When an Italian tells me it's pasta on the plate, I check under the sauce to make sure. They are the inventors of the smoke screen."

On Real Madrid's hopes of signing Cristiano Ronaldo before the Spanish side succeeded in 2009: "Do you think I would get into a contract with that mob? Jesus Christ, no chance. I wouldn't sell them a virus."

After the Champions League final in 1999 when United scored twice in the closing minutes to beat Bayern Munich 2-1: "Football, bloody hell."

On the 2003 incident in which United midfielder David Beckham was struck accidentally on the head by a flying boot kicked by Ferguson: "It was a freakish incident. If I tried it 100 or a million times it couldn't happen again. If I could I would have carried on playing!"

On post-match drinks with Jose Mourinho, who won the Premier League twice as Chelsea manager: "It would help if his greetings were accompanied by a decent glass of wine. What he gave me was paint-stripper."

On Rafael Benitez, whose stints in charge of Liverpool and Chelsea have been marked by spats with Ferguson: "I think he is very concerned about his CV. He refers to it quite a lot."

On media coverage of his argument with Newcastle manager Alan Pardew this season: "The press have had a field day. The only person they have not spoken to is Barack Obama because he is busy."