Sir Alex Ferguson is widely regarded as the greatest manager in Premier League history. 

He guided Manchester United to a ridiculous 13 titles, while also winning five FA Cups and two Champions Leagues during his 27-year tenure at Old Trafford. 

The Scotsman also managed some of the greatest players on the planet - including one Cristiano Ronaldo.

Ferguson is often credited with shaping him into a world-class footballer and made no secret of the fact he always backed CR7 to be the best. 

But in his younger years at Man United, the Portuguese was sometimes accused of being a diver and going to ground too easily to win free-kicks and penalties. 

That's a claim Sir Alex refuted - and Sky Sports reporter Geoff Shreeves once found that out the hard way when the coach 'came after him' in the tunnel. 

Following a fixture against Middlesbrough in 2006, Shreeves questioned Ronaldo's antics in winning a penalty when goalkeeper Mark Schwarzer appeared not to touch him. 

Ronaldo and Ferguson had a good relationship

You can see the incident below:

His accusation left Ferguson fuming and led to things nearly getting physical in the tunnel.  

"The biggest [issue] was Cristiano Ronaldo going over for a penalty against Middlesbrough," Shreeves wrote in his column for The Times, per the Mirror.

"We had a huge falling out which threatened to get very out of hand in the tunnel. Fergie came after me physically, never got there. People jumped in." 

Fergie was ready for a fight

Shreeves claims that Sir Alex then told him to 'f*** off', to which the reporter replied: "Don’t talk to me like that. If you want to behave civilly, fine." 

Incredibly, after cooling off following the incident, Shreeves came to the conclusion that Ferguson was right to go after him and went to smooth things over with the legendary manager.  

"Fergie was in the right and I was in the wrong and I addressed that with him. We sorted it out very amicably, very quickly and it was never mentioned again."

Shreeves apologised to Ferguson in the end

Crazy. You've got to admire Shreeves for his reaction that day. 

After being told to 'f*** off' and threatened by the Man United manager, he made sure to smooth things over after. Fair play. We certainly wouldn't want to be in Sir Alex's bad books, either!