The German coach has heaped praise for the way in which the Frenchman responded to being ordered to work harder for his team-mates after the 2012 Champions League final loss
The Frenchman received Uefa's Best Player in Europe Award on Thursday, beating Lionel Messi and Cristiano Ronaldo to the prestigious prize.
Heynckes felt that Ribery's triumph was fully merited, given the way in which the attacker has transformed himself into the ideal team player since Bayern's devastating 2012 Champions League final defeat at the hands of Chelsea.
"You fully deserve to be European Footballer of the Year for 2013," the 68-year-old wrote in an open letter to Ribery in Kicker. "You were the best! I'm so happy for you and I congratulate you with all my hear.
"We worked together every day in recent years and have built up a special relationship. I always knew that you are a feel player who needs the confidence of the coach.
"During this time you have developed yourself tremendously as a person, and especially as a professional footballer.
"Sure, we had our fights. After the defeat in the Champions League final in 2012, I told you - just as I said to Arjen Robben - that you needed to work back more if we were to achieve something great. I threatened you with the bench.
"But you have proven that you are a team player. You wanted success for the entire team and have invested your great individual skills in the success of the overall plan.
"So, after the success of the collective you have reached this personal triumph. For your unselfish attitude, you have been rewarded."
Ribery played a key role in Bayern's treble triumph last season and will be hoping to help the Bavarians pick up another trophy when they tackle Chelsea in the Super Cup in Prague on Friday.