In soccer, the English Premier League or EPL is widely regarded as one of the best leagues in the world along with Spain's La Liga and Italy's Serie A.
As the EPL season is drawing closer to the end, tensions are rising between the title contenders; defending champion Chelsea following closely on the heels of the current leader Manchester United.
The tensions rose to fever-pitch this week when Chelsea's outspoken manager Jose Mourinho alleged that Manchester United have benefited from refereeing bias this season.
Although Manchester United's manager Alex Ferguson gave a pass to Mourinho's barbs, Man United's supremely confident Ronaldo decided to jump in against his countryman.
In a remarkable exchange of insults, Portuguese television viewers were treated to their country's most famous manager accusing their country's most famous player of "lying" and warning Ronaldo that he would never be the best player in the world.
Mourinho was responding to a slight from Ronaldo that the Chelsea manager did not "know how to deal with his failures".
With Chelsea on for an unprecedented quadruple of trophies, and United chasing the treble, feelings are understandably running high.
The latest saga began after his Chelsea's draw with Newcastle, when Mourinho announced, tongue-in-cheek, that there were "new rules" that dictated his side would not be awarded penalties and that United would not have penalties awarded against them.
When the competition is this intense, managers of the top teams routinely indulge in playing mind games before the players take to the field, in order to gain a psychological advantage over opponents.
We saw the ugly side of players behaviour in the world cup final of 2006 between France and Italy played in Germany.
Zinedine Zidane, a three-time FIFA world player of the year, who is known to have a temper, was touted throughout the match by the Italian defender Materazzi, calling names and hurling him abusive language.
In the dying minutes of the evenly balanced game , to everyone's surprise, Zidane head-butted Materazzi. Zidane was ejected from the match, unceremoniously ending a glorious career. France lost the match on penalties plunging a nation into mass mourning.