His body language was different, he was smiling at the team, but that’s not Novak," Mouratoglou questions Djokovic's motivation at Roland Garros
On his Instagram account, Osaka’s coach, Patrick Mouratoglou, reflected on Djokovic’s last match at Roland Garros. The Serb was defeated by Sinner in the tournament’s semifinals (6-4, 7-5, 7-6). For the Frenchman, the behavior of the Grand Slam record-holder didn’t seem the same as usual:
"His tennis was there, and I thought he could beat Jannik. He’s won many matches like that in the past, and most of the time, he’s found a way to turn things around. Physically and game-wise, he was there, but winning this kind of match isn’t just about tennis—it’s about mentality.
I felt like he had accepted Sinner’s dominance. I didn’t see the Novak I know, and I still think his motivation wasn’t high enough. His body language during the match was different. He was smiling at his team, enjoying the moment—that’s not Novak. He’s a fighter. Now, he’s happy just being in a Grand Slam semifinal and competing against these guys. It’s no longer a matter of life or death.
In the Olympic final, on this same court, he was a bull ready to do anything to win. Back then, it was a matter of life or death. Proving he was the best in the world was the motivation he had before, when fans supported Federer and Nadal. I think that’s what really drove him. Now, he’s lost that edge because he’s become the greatest.
French Open 
Djokovic is wise enough to realize when his old body doesn't show up and no matter whether he's a fighter or not, if the body says 'you want me to do what?', it's not going to be a good day.