Jose Mourinho's struggles in the transfer market this summer have been well documented.

One position that he desperately tried to strengthen was the centre-back position.

It was believed he chased deals for Toby Alderweireld, Harry Maguire and Yerry Mina, but he failed in deals for all three.

With time running out and Mourinho still keen on signing a centre-back, the Portuguese manager looked elsewhere.

One man that was heavily linked with Man United in the final days of the transfer window was World Cup winner, Jerome Boateng.

The German defender has proven himself as a world-class player in the past few years and Mourinho was believed to be keen on bringing him to Old Trafford.

But a deal was never completed between United and Bayern Munich. Why exactly did the move fail?

Boateng has now opened up about the failed move. He has recalled why his move to United failed and what he told Mourinho on the phone when informing him of his decision.

"I had enquiries from PSG and Manchester United," Boateng told Bild, per the Metro.

"I did not want just to get away from Bayern, but I was thrilled to try a new challenge.

"I feel well at Bayern. It’s one of the biggest clubs in the world.

"I called Jose Mourinho, I told him that his interest was an honour for me and thanked him for trying so hard for me.

"I explained to Jose that it’s difficult to leave Bayern, and if I do, everything has to be in place to top this club."

So there we have it. It seems Mourinho tried his best to make a deal happen for the German international, but the German refused to join as everything was not in place at Old Trafford.

However, Boateng showed his class during the phone-call and Mourinho will no doubt have appreciated his honest words.

Alderweireld also also heavily linked with United, but he insisted on Tuesday that he was never close to leaving Tottenham.

"Everyone was saying everywhere that I absolutely wanted to leave Tottenham," Alderweireld said, per Sky Sports.

"That's not true. This summer, I quickly understood Tottenham wanted to keep me. So, I had to battle to get my place back in the team. To be in the first team again is a victory for me.

"I just try to help Tottenham as best I can with my qualities. Regarding my future, everything that was said in the press was not right all the time."