The 19-year-old rallied from a set down to overcome Djokovic 3-6 6-3 7-5 and deny the Serb a seventh title in the tournament, capping off a spectacular run in which he also beat four other top-10 players.
“To beat Novak. To be able to beat him in such occasion … in the final is probably the best feeling of this whole week,” said Rune, who defeated Hubert Hurkacz, Andrey Rublev, Carlos Alcaraz and Felix Auger-Aliassime en route to the title clash.
“It was also important for me to beat Felix and Alcaraz and these guys. But still, to be able to beat Novak … he’s probably one of the greatest we have ever had in this sport.
“It’s a crazy feeling.”
Rune, who climbed to world number 10, withdrew from the Next Gen ATP Finals and will now head to Turin as the first alternate at the season-ending ATP Finals, which begins on Sunday.
“Of course I’m going to go to Turin. I’m one out. I mean, I wish all the players that I’m not going to play, because I wish them to be healthy, but at the same time it would be awesome if I got to play,” Rune said.
“I didn’t expect that at all four or five weeks ago but now I’m here. I’m super happy how I officially ended my season, and if there possibly is more matches, I’m super excited for it.”