Borussia Dortmund CEO Hans-Joachim Watzke has claimed Chelsea refused to sell them Kevin de Bruyne because they were still bitter about their failed pursuit of Robert Lewandowski.
De Bruyne is now one of the Bundesliga's biggest stars after a stellar 18 months as a Wolfsburg player. Having picked him up for just under £17m in January 2014, the Holland international has proved to be an excellent acquisition.
So much so that he has already been linked with a return to the Premier League with Manchester City and Manchester United both being linked with a £35m move this summer.
Now fans of Borussia Dortmund and Bayern Munich are wondering why their clubs did not see how much potential the then-22-year-old had.
But Watze said has now revealed that Dortmund tried hard to sign De Bruyne, but were told by Chelsea that they would have no chance of signing him because they were still bitter about being rejected by Lewandowski.
"It [signing De Bruyne] would have fitted well into the planning'" he told Bild.
"But the conditions could not be agreed. Chelsea were unwilling to let him go because they were angry that Robert Lewandowski had not gone to Chelsea."
The Lewandowski saga
Lewandowski left Dortmund in 2014 on a free transfer to Bayern Munich. While there was no official confirmation until June, it was understood for some time before that the Pole would move to the Allianz Arena.
That did not stop Mourinho getting in a huff about his failure to coax the striker to Stamford Bridge, however.