The Premiership title race heated up several degrees today when Cristiano Ronaldo and Jose Mourinho, Portugal's two finest exports, started a slanging match in their home nation's media.

Ronaldo said that Mourinho “doesn’t know how to admit his own failures” after the Chelsea manager’s recent complaints about the awarding of penalties.

Mourinho claimed on Sunday that “new laws” applied to Manchester United but not to Chelsea, after his side were denied a penalty in the goalless draw at Newcastle United. A day earlier United had been fortunate not to concede a late penalty against Middlesbrough at Old Trafford.

“We all know how he is,” Ronaldo, the PFA Player of the Year and Young Player of the Year, told Portuguese TV. “He always has to say something when he is not happy. Jose Mourinho doesn’t know how to admit his own failures.”

Mourinho responded by saying that Ronaldo will “never reach the level that he wants to reach” unless he accepts “facts”.

“A player who wants to be the best one of the world, and he already may be, should have the uprightness and the sufficient maturity to verify that against facts there are not arguments," Mourinho said.

“If he says that it is a lie that Manchester United have conceded some penalties this season which have not been awarded against them, he is lying. And if he lies he will never reach the level that he wants to reach.”

Carlos Queiroz, United's assistant manager, said: “Mourinho has his own style, he always tries to divert everyone’s attention to the points which are convenient for him. These are his tactics and that’s the way he is.”