Benfica do not want to sell Enzo Fernandez, says Roger Schmidt, who has been angered by Chelsea's approach for the midfielder.
Chelsea want to sign Fernandez, who only joined Benfica from River Plate last year, on the back of the 21-year-old's excellent World Cup displays for Argentina in Qatar.
A deal looked likely to be struck earlier this week when reports claimed Chelsea were willing to meet the release clause in Fernandez's contract, which is rumoured to be £106million (€120m).
That would make Fernandez a record signing for a Premier League club, yet reports on Wednesday suggested the proposed move had hit a stumbling block after Chelsea attempted to negotiate a lower fee.
In his pre-match press conference ahead of Benfica's meeting with Portimonense, Schmidt appeared to confirm these reports as he hit out at what he believes are underhand tactics.
"We don't want to sell Enzo, neither I nor the president," he told reporters on Thursday.
"We all know he has a clause in his contract. If he wants to leave and if someone meets this clause, we can do nothing.
"There is a club that wants the player, that knows we don't want to sell, that tries to put the player on their side when they know that the only way to get him is to beat the clause.
"The situation is very clear. What that club is doing to try to sign Enzo is [showing] a lack of respect for Benfica."
"I cannot accept what they are doing. They try to drive the player crazy, pretending they're going to pay the clause and then say they want to negotiate.
"I think that's not the way for two clubs to have good relations."
Fernandez missed multiple training sessions last week, having returned to Argentina without Benfica's permission.
"Enzo is a very good boy and a fantastic player. We like him very much and we want him to stay. But his situation is not easy," Schmidt explained.
"He played in a World Cup, was world champion and there's a lot of money on the table.
"A player can get confused when he thinks about it and I think it's a situation that everyone understands. He wasn't allowed to go to Argentina, he missed training and that's not acceptable. There will be consequences, I won't say what."