The meeting ended with a score of 6: 3, 6: 2.
Thus, the Serbian tennis player secured an access to the semifinals of the ATP Final Tournament.
He has already won two matches in a row.
Russian tennis player Daniil Medvedev became the first to make it to the semifinals of the tournament.
Rublev suffered his first defeat at the Final Tournament in Turin.
In the third round of the group stage, he will face the Norwegian Kasper Ruud.
Earlier Sinner said: "To beat Medvedev, you need to show your maximum."