Had he not have scored and Bayern Munich gone on to win, he admits he may have been tempted to stay but, with all his loose ends tied up, he is moving on to a new chapter.
Speaking to Radio Five Live, he said: "I think winning the game was the key. Not me scoring the penalty. Winning the game was the turning point, that's why I have decided to say goodbye.
"We made the story together and I want people to remember that. This is the best time to move on.
"Yes, there's a chance that if the result was different, maybe I would be here.
"We were talking for many weeks, but the turning point was based on the fact I won everything I could and scored in most of the finals we have played, trying to make a difference. I hope everyone will understand. Everything I did was for the fans and I hope they understand."