Maurizio Sarri has accused Bayern Munich of not respecting Chelsea after the German champions publicly declared their interest in signing Callum Hudson-Odoi.

Chelsea are still considering Bayern’s fourth offer of £35m – a fee that would make the 18-year-old forward the most expensive English teenager in history – having made no progress in their attempts to persuade him to sign a five-year contract first offered last summer. The England youth international is understood to be determined to leave Stamford Bridge, with a decision expected to be taken following Saturday’s game with Newcastle.

But Sarri, who also admitted the £58m Álvaro Morata could leave on loan this month, could not hide his anger after Bayern’s sporting director, Hasan Salihamidzic, said on Wednesday that Hudson-Odoi “is a very interesting player whom we really want to sign”.

Bayern Munich raise offer for Chelsea’s Callum Hudson-Odoi to £35m Read more

Sarri said: “I think it’s not professional, because they are talking about a player under contract with Chelsea. So they didn’t respect our club.”

Hudson-Odoi has started the last two matches in the FA Cup and Carabao Cup and is expected to be involved against Newcastle despite the uncertainty over his future. Borussia Dortmund’s Jadon Sancho, who played with him at England under-17 level and remains a close friend, revealed on Thursday he had spoken to Hudson-Odoi and “told him the Bundesliga is a nice league. I just told him to do whatever is best for him and whatever makes him feel comfortable”.

In line with several players and the assistant, Ginafranco Zola, all of whom have urged Hudson-Odoi to stay at Chelsea, Sarri was full of praise for the player’s progression. “We are very happy with the player because he is improving. He is improving a lot I think in the defensive phase. Now, he needs to improve in some movements without the ball. He is working very well and I’d like to have him in the future.”

Chelsea are under investigation by Fifa over possible violations of rules on the signing of foreign players under the age of 18 but have looked into whether they have grounds to report Bayern for approaching Hudson-Odoi illegally.

With Morata potentially in line for a move to Sevilla and Cesc Fábregas completing his switch to Monaco, Sarri said he has identified his targets in this window following the signing of Christian Pulisic from Borussia Dortmund, who will arrive in the summer.

“I spoke with the club and the club knows very well my opinion,” he said. “In my opinion we need two players. Then it depends on the club decision.”

An offer from Barcelona for Willian, who like Hudson-Odoi and Eden Hazard is out of contract in 2020, that involved a swap deal with Malcom, has been rejected.

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“He is really very important,” Sarri said. “I think he can do better. He can do better because the potential is higher but he is really very important for us and it is impossible to lose him in January.

“Usually he wants the ball always on the feet and so he can improve in his movements without the ball and he has the potential to score more.”