I translated some of the important things he said in this video to Another poster yesterday, but this is what he said in short:
He thought his game was pretty bad and that he wasn't close to his top level. He also said he played without a serve for majority of the match. Then proceeded to say in the most important moments, he raised his level. He also said he was relieved they came to that 12-12 TB.
Mentally, according to him, it was the toughest match he ever had. Mostly cause of the crowd being against him (wich he already knew they were gonna be) but also cause of how he struggled with his game and having to win on sheer mental strength. Interviewer also asks him how he managed to stay so calm throughout the match, and Djokovic said that is what he was the most satisfied with. He promised himself before the match that he was not gonna let the crowd get to him and he is very happy that he held that promise to himself.