It was a slow burner for a while, but the rivalry between Manchester United boss Jose Mourinho and Chelsea chief Antonio Conte has really ramped up in the last few weeks.
The Portuguese and the Italian have gone head-to-head as they've traded insults on hair transplants, match-fixing and being a "clown" - and the war of words can be traced back to the beginning of last season.
Here's a timeline of just what they've said about each other.
And there's a lot of it.
October 2016 - Mourinho accuses Conte of "humiliating" him with celebrations after Chelsea beat United 4-0
Italian TV reportedly caught Mourinho saying: "You don't celebrate like that at 4-0, you can do it at 1-0, otherwise it's humiliating for us."
November 2016 - With Victor Moses shining in his team as a right wing-back, Conte wonders why Mourinho constantly overlooked the Nigerian and sent him out on loan
"I noticed his potential from the first days of the summer retreat," Conte told Gazzetta dello Sport.
"Moses has important qualities: technique, physical strength, the ability to cover seventy metres of the pitch. I find it incredible that someone like him has been overlooked."
February 2017 - Chelsea sit top of the league, but Mourinho calls them "a defensive team"
"Chelsea are a very good defensive team.
"They defend very well and with lots of players and I think in this situation a very defensive team wins the title with counter-attack goals and set-pieces goals, so I don't think they will let it slip but football is football."
March 2017 - Ander Herrera is sent off as Chelsea beat United 1-0 in the FA Cup, with Blues fans baiting Mourinho and calling him "Judas"
“The fans can call me what they want.
“I am a professional. I defend my club. Until the moment [Chelsea] have a manager that wins four Premier Leagues for them, I’m the No1. When they have somebody who wins four Premier Leagues for them, I’ll be No2. For this moment, ‘Judas’ is No1.”
Conte on United's treatment of Eden Hazard in the same game
“We’ve got to play football but for 25 minutes it was impossible for Hazard to play football.
"I see only that he got a lot of kicks. Only kicking. He started the game receiving kicks, and he finished receiving kicks.
“This is not football for me. I don’t think this can be a tactic. This is the truth. Everyone saw this. I think sometimes, when you play against players with great talent, you try and intimidate these players. I think the referee must protect this type of player. What happens if they are put out with a bad injury?”
April 2017 - Conte criticises Manchester United's spending
"I think this season it's very important to understand that it's not always who spends more money who wins.
"Otherwise, in this league this season, the name of the team (who would win the title) wasn't Chelsea or Tottenham or Arsenal or Liverpool. You understand?
"This season isn't the only season the Manchester clubs have spent a lot of money. Look at the past. It's normal."
July 2017 - Conte hopes to avoid "a Mourinho season" at Chelsea after winning the league, Mourinho responds with a dig about Conte's hair transplant
"Two years ago Chelsea finished 10th. That cannot happen again. We know the difficulty and for sure we want to avoid the Mourinho season with Chelsea.
"The coaches of the previous two champions [Chelsea and Leicester] both lost their jobs [the next season] and we are working very well to find the best solutions and use them."
Mourinho responds with: "I don't know. I could answer in many different ways but I'm not going to lose my hair to speak about Antonio Conte."
October 2017 - Mourinho takes a swipe at Conte for "always talking about injuries" - with Conte responding by claiming his rival is obsessed by Chelsea
"I never speak about injuries. Other managers, they cry, they cry, they cry when a player is injured.
"I don't cry; I think the way to do it is ignore the players who are injured and focus on the players that are available. If I want to moan and cry like the others, I can cry for the next five minutes. But I don't."
Conte replies with: "I think he has to think about his team and start looking at himself, not others. I think that, a lot of times, Mourinho [likes to concentrate on] what is happening at Chelsea. A lot of times, also last season. [He has] to think about his team."
January 2018 - Mourinho refers to Conte's often manic celebrations on the touchline, calling him a "clown", with Conte hitting back by accusing his rival of being "demenza senile"
"Because I don't behave as a clown on the touchline, it means that I lost my passion," he said.
"I prefer to behave the way I am doing it, much more mature, better for my team and myself, I don't think you have to behave like a crazy guy on the touchline to have that passion."
Conte responds: "I think he has to see himself in the past - maybe he was speaking about himself in the past. Maybe, sometimes, I think that someone forgets what's said in the past, which is his behaviour," he said.
"Sometimes I think there is, I don't know the name, but demenza senile... when you forget what you do in the past."
January 2018 - Mourinho refers to Conte's match-fixing suspension
"What never happened to me - and will never happen - is to be suspended for match-fixing. That never happened to me and will never happen."
January 2018 - Conte calls Mourinho "a little man"
I think when there are these types of comments, comments where you try to offend the person and don't know the truth, then you are a little man," he said.
"In the past he was a little man in many circumstances, he's a little man in the present and for sure he will be a little man in the future. I consider him a little man and I consider him a man with a very low profile."