Ruud van Nistelrooy says he still regrets leaving Manchester United in controversial fashion 13 years ago.
And the striker admitted he took the first steps to mend their broken relationship.
"It was very harsh, both ways," he told Eleven Sports.
"Especially after five years of having such a strong bond. I learned so much from him, and in all modesty: he from me too.
"And yet the end was ruthless."
He added: "It was me who took the first step to make it okay again. I called him. A few times a year I felt bad about what I had done to him and the names I called him when he kept me on the bench the entire match in the League Cup final in Cardiff. In a blind rage I shouted at him.
"I called him something. I called him a number of things in a blind rage. Cocky and stubborn as I was, I couldn't snap out of that for some time after. That's how it all crashed.
"It was just really disrespectful, there were lots of other people there. It wasn't all that outrageous in terms of words but it was completely out of order. Not done.
"I wasn't proud of it, still am not."