Former Manchester United manager Louis van Gaal has revealed the club failed with a bid to land striker Robert Lewandowski.

The bid came a year after Lewandowski joined Bayern Munich from Borussia Dortmund in 2014, with Bayern refusing to entertain any offers for their star striker.

“He is currently the best striker in the world. I also wanted to train Lewandowski and wanted to bring him to Manchester United,” Van Gaal told Bild.

“The price was not a problem for Manchester United, but Bayern did not want to let him go.”

In the same interview, Van Gaal criticized his former United charges for not getting on board with a system he tried to implement of tracking players’ form via email.

“I sent emails to players. It highlighted their strengths and weaknesses.

“I developed the digital tracker with an IT man. Each player could log in. Through that, I allowed them to prepare at home for our conversations before meeting me one-on-one.

“You might ask why the surveillance but, even today, I think that’s professional.”

United’s players felt betrayed by the system, Van Gaal admits, but says the setup worked for him when he was Bayern manager.

“But it shows their lack of professionalism, and I addressed that,” Van Gaal said of United players’ reluctance.

“I did this with Bayern. I believe that a full professional also wants to live as a professional. Like Arjen Robben. He read those emails.”