In a scene reminiscent of his touchline dash at Old Trafford in 2004, when his Porto side scored a late equaliser against Manchester United, the Portuguese manager did it again at the weekend after Roma grabbed a late winner against Sassuolo.
And he now admits it was because he'd been so fearful that the landmark day wouldn't go to plan and says when the goal went in it felt like he'd been transported back to being a young boy again.
He said: "I wasn't 58 years old, but 10 or 12 or 14, when you start dreaming about a career in football.
"Running like I did, I was running like a child.
"And I apologised to (Sassuolo coach Alessio) Dionisi for that."
And Mourinho now admits he was previously "lying" when he suggested the fixture didn't hold any particular significance.
He said: "During the week I was lying to people, telling everyone this wasn't a special game - perhaps I was trying to convince myself as well.
"But actually it was - this game had a really special meaning for me.
"And I am sure I will remember it for the rest of my life, because my 1000th game as a coach was this one.
"I didn't want to lose it, and I was very scared of having that be my lasting memory of the moment.
"So I was lying to everyone beforehand. It was a very special feeling.
"Perhaps God decided that I didn't deserve to have a negative memory of this particular game."