Jose Mourinho has had his faire share of feuds with opposition managers but while his relationship with the likes of Arsene Wenger and Rafa Benitez has been tense, the war of words between himself and Chelsea manager Antonio Conte have been getting a little ugly and personal.
Manchester United and Chelsea don't face each other again on the field until February 25th which may give a little time to take the heat away from a enmity which has been brewing since 2016.
Manchester United manager Jose Mourinho (left) and Chelsea manager Antonio Conte. Adam Davy/PA Wire/PA Images
"Mourinho was nipping away for a wee while and I think a lot of it was Mourinho," ex-Chelsea and Everton winger Pat Nevin told us of the origins of the feud as former Scotland international joined us as always on a Monday.
"And Conte was just shrugging his shoulders and saying, 'Well, I'm top of the league, I'm winning the league, I don't care'.
Manchester United manager Jose Mourinho during the FA Cup, third round match at Old Trafford, Manchester. Martin Rickett/PA Wire/PA Images
"But he's nipped into action and Mourinho's great at that. But see the whole "fake" thing - Conte saying that Mourinho's "a fake" as if to say, 'Do you want to stand beside me?' - because I've watched them face each other down and Mourinho walks away."
Although he added that Mourinho trying to wind up opposition managers is part and parcel of the game, Pat added, "I just don't think it's necessarily worked with Conte... yet".
