10 Training Ground Feuds You Probably Didn't Know About

7. Ruud van Nistelrooy And Cristiano Ronaldo

One of the iconic shots of 2004 European Championships was an act of acknowledgement and respect in diversity. Following Holland's gut-wrenching semi-final exit at the hands of hosts Portugal, Manchester United colleagues Ruud van Nistelrooy and Cristiano Ronaldo became embroiled in a warm embrace upon the sounding of the full-time whistle. Within two years, their relationship would have soured beyond repair. Two of the Sir Alex Ferguson's most potent goal-scoring threats, they struck up a fine rapport on the pitch, but as time went on, the former PSV hitman grew frustrated at Ronaldo's unpredictability.

''He'd say: 'I don't know when he's gonna cross the ball. How can I make my runs? I look like a fool.' Ruud was reliant on other people to put chances his way, so when Ronnie came along and he was about skills and showboating, he used to go mad. There were tantrums.'' - Rio Ferdinand, December 2013.

It all got a bit too much for the Dutchman as the 05/06 petered out, with Chelsea romping to their second title by a clear distance. While Van Nistelrooy was still bagging the goals, Ronaldo was clearly the new golden boy at Old Trafford. Furious at his omission from the 2006 Carling Cup final line-up against Wigan Athletic, he chose the Portuguese starlet as the perfect medium to vent his spleen. Following a few heated exchanges in training, he chose to mock his close relationship with assistant coach Carlos Queiroz, suggesting that he 'go and talk to his dad'. Innocuous in its' intention, it was ultimately a clearly insensitive and thoughtless remark, considering the former Sporting Lisbon winger's father had passed away the previous September.