Good Delusion
In order to be a tennis great, you have to be somewhat delusional. Once you start that delusion, it's hard to turn it off. Novak operates on a different mental level than the average top player or even most past tennis legends. He is something else. Is he just insane? Perhaps. He might be delusional, but it's that delusion and obsession that have created a mentality we have never seen before.
The type of dude who wants to find all possible solutions from within himself, even if that's delusional a lot of times. That's how he got here.

Bad delusion
- "Couldn't win because of Big 3"
- Saw Federer comment on slow courts >>> Immediately goes and complains about it to make more excuses for his lack of progress. "They want Sincaraz to win." > Goes on to lose to someone outside the top 50 immediately after. Zero self-awareness.
The type of dude to externalize all his issues (and be so delusional about it) so he doesn't bother to look within and actually work to improve. Complete opposite of Djokovic.
Conclusion: Talent without an elite mindset is Zverev or Tsitsipas at best. Talent and great fitness can only take you so far. Maybe you just can't build a mentality like Big 4 or Sampras. You either have it or not? I believe it's possible to build, however, but no chance of that happening with a massive ego that externalizes issues non-stop.
The next star has to have a true elite mindset and someone who takes accountability for their shortcomings. If that player has too much of an ego to and mostly externalize his issues, then it's all false hope (like it was with Z and Tsitsi).
Thiem had an elite mentality despite his shortcomings. Shame about the injuries.