The youngster overcame world number one Djokovic 3-6, 7-5, 6-3 to advance to the semis.
Tsitsipas will take on Russia's Daniil Medvedev next, who overcame Fabio Fognini 6-3, 7-6.
Here is more on the same.
Tsitsipas has beaten Federer, Nadal and Djokovic this season
Tsitsipas has quickly established himself as one of the star players.
The Greek international also beat Djokovic for the second time in his career.
He has now beaten Roger Federer (Australian Open), Rafael Nadal (Madrid Open) and Djokovic in the same season.
"I did dream of that (beating them all), not in the same season though but it's happened, it's so cool," Tsitsipas exclaimed.
Really happy with the win, says Tsitsipas
"I played really well. I felt in the zone in the second and third. I was confident that I could match him from the baseline. My serve worked really well today. Really happy with the win," said Tsitsipas after his victory.
Tsitsipas has qualified for the season-ending ATP Finals
With this win over Djokovic, Tsitsipas also secured his qualification to the season-ending ATP Finals in London.
He was elated and admitted that he had no idea of the qualification.
"No way, really? I really had no idea, it is secure, seriously? YES! I wasn't looking at the rankings and but I am so happy to have qualified for the ATP Finals," he claimed.
I didn't make him defend enough, says Djokovic
"He was backing up his serve with really good and aggressive first shots in the rally. I didn't make him defend enough. I just gave him enough time to really dictate the play from back of the court and he deserved to win," said Djokovic.