Selling Kevin de Bruyne is one of Jose Mourinho's biggest mistakes at Chelsea.
Signed for £7 million from Genk in 2012, De Bruyne would spend the following season with Werder Bremen.
It is with the German club that he impressed.
He made 34 appearances for Die Werderaner, where he scored 10 times.
De Bruyne was also named Bundesliga Young Player of the Year.
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There was a lot of excitement upon his return to Chelsea.
However, De Bruyne would only make nine appearances in the 2013/14 season, most of those coming from the bench, before leaving for Wolfsburg in January.
That proved to be a huge mistake by Chelsea.
De Bruyne had great success in Germany and has since become one of the world's best players at Manchester City.
There is no doubt that he would be one of the first names on the team-sheet if he was still with the Blues.
Mourinho's decision to sell De Bruyne was a head-scratcher and now the Belgian has opened up about the conversation the two had prior to him leaving.
Writing in the Players' Tribune, the 27-year-old said: "When I came back to Chelsea the next summer, a few German clubs wanted to sign me.
"Klopp wanted me to come to Borussia Dortmund, and they played the kind of football that I enjoy. So I thought maybe Chelsea would let me go.
"But then Mourinho texted me, 'You are staying. I want you to be part of this team.'
"So I thought, O.K., great. I’m in his plans.
"After the fourth game, that was it. I was on the bench, andI never really got a chance again. I didn’t get an explanation. I was just out of favor for some reason.
"José called me into his office in December, and it was probably the second big life-changing moment for me. He had some papers in front of him, and he said, 'One assist. Zero goals. Ten recoveries.'
"It took me a minute to understand what he was doing.
"Then he started reading the stats of the other attacking forwards — Willian, Oscar, Mata, Schürrle.
"And it’s like — five goals, 10 assists, whatever.
"José was just kind of waiting for me to say something, and finally I said, 'But … some of these guys have played 15, 20 games. I’ve only played three. So it’s going to be different, no?'
"It was so strange. We had a bit of a conversation about me going back out on loan. And Mata was also out of favor at the time, so José said, 'Well, you know, if Mata leaves, then you will be the fifth choice instead of sixth.'
"I was completely honest. I said, 'I feel like the club doesn’t really want me here. I want to play football. I’d rather you sell me'."
After leaving, it didn't take long for De Bruyne to make Mourinho regret his decision.