A ball has yet to be kicked in anger this Premier League season, but Jose Mourinho has wasted no time getting stuck into Arsene Wenger and Jurgen Klopp by branding them "not ethical".
As the Manchester United manager gave the clearest indication yet that Paul Pogba is set for an imminent return to Old Trafford, he could not resist having a dig at the Arsenal and Liverpool bosses.
The pair have questioned the world-record fee of £100million which appears to be the amount it is taking to prise the France midfielder from Juventus.
Asked whether a big signing could be expected over the next few days, the Portuguese said: "Yes."
When he was then asked if he was confident it would be Pogba, Mourinho said: "I don't like to speak about other clubs, or about players from other clubs.
"Other managers like to do that. They like to speak about my club and my players.
"I am very pragmatic on this. The only thing that matters for me is what happens in my house, not in the house of my neighbours.
"Pogba is a Juventus player until officially he isn't, so we stay like this.
"But honestly, the market closes on August 31, but I think my club is trying to do everything to close our market before August 14. So next week we will have our squad closed."
Mourinho - who has also signed Eric Bailly, Henrikh Mkhitaryan and Zlatan Ibrahimovic this summer - added: "I only speak about us. I heard already two of my colleagues from other clubs speaking about us. I do not like that. It is not ethical.
"There are things that when I do (them), it is not ethical but when others do (that), nobody says that and everything is normal.
"But the reality is I don't speak about the others. They can do what they want.
"I think our market was good. We made decisions. We decided to bring four players, not 10, that are Man United level and that we think can really improve the squad and not just be one more. This is a profile of our market.
"We have a young central defender who needs time to be a top one but has top potential and we believe a lot in him, we bought a creative player and we know the quality he has, we bought a super striker and we are going to get a very good midfield player. So we try to give balance.
"So I am happy with my squad and with the effort the club did and is still doing for us, and the others - it is their problem. They can do what they want."
Last month Wenger described the proposed Pogba deal as "complete madness", while Klopp was quoted as saying: "'If you bring one player in for £100m and he gets injured, then it all goes through the chimney.
"The day that this is football, I'm not in a job any more, because the game is about playing together."
Mourinho, who in 2014 called Wenger a "specialist in failure", aimed his latest barbs on Friday as he spoke at his press conference to preview Sunday's Community Shield clash with Leicester, which is seven days before United's Premier League opener at Bournemouth.
While it appears merely a case of exactly when rather than if Pogba is announced as a United player - Mourinho also said of his squad "we have 22 (players) now and we are going to have 23" - it seems clear as well that fellow midfielder Bastian Schweinsteiger will not be with the club for much longer.
Amid reports he was training with the reserves, Schweinsteiger was absent from both the recent friendly win over Galatasaray and Wayne Rooney's testimonial match against Everton.
With the World Cup winner looking to have been cut out of the first-team picture at United, Dejan Stefanovic, a lawyer and FifPro member from Slovenia, suggested this week that Mourinho should be sent to prison over his "bullying" treatment of Schweinsteiger.
But Mourinho played things down on Friday when he was asked about the Schweinsteiger situation.
"What is happening is what is happening in every club in the world, which is the manager decides the squad and chooses a certain number of players to face the season and that is it," Mourinho said.
"I made the decision to be with 23 players plus three goalkeepers, and I had to make my decisions. It is simple."