The 49-year-old Irishman was Ipswich Town manager at the time and was holding his pre-match press conference.
During the press conference, Keane showed little sympathy for Ireland as he weighed in on the country's failure to qualify for 2010 World Cup after Thierry Henry's handball for France.
But Keane's press conference took an interesting turn when a reporter's phone went off the second time, earning a rise from the former Ipswich boss himself.
"Whose phone is that? That's the second time it's gone off," he said.
"Why don't you turn it off? It's the second time that it's gone off. Why don't you put it on silent? Why don't you turn it off?"
The reporter responded back to Keane by saying that he would "turn it off in a minute" before adding that he plans to "let it ring out."
However, that response didn't sit well with Keane as the former United skipper brutally put the reporter in his place.
"You're just going to let it ring? Oh, right, that's good manners," the former Nottingham Forest star said.
Keane's no-nonsense attitude, which he was widely praised for during his illustrious playing career, earned him praise from fans over his confrontation with the reporter.
"One thing I like about Roy Keane is that he is true to himself, never change and doesn't give a s**t about what media or anyone thinks about him," one fan said.
While another posted: "The way he scans the room when it goes off actually has me gone."
A third said: "The Roy Keane death stare... that journalist has been added to the long list of enemies somewhere in between Mick McCarthy and David de Gea."
A fourth added: "Roy Keane says 'turn it off,' you best turn it off."
Keane was sacked by Ipswich in 2011 and went on to become assistant manager at the Republic of Ireland, Aston Villa and Nottingham Forest.
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