Novak Djokovic beat Russia's Karen Khachanov 4-6, 7-6 (7/0), 6-2, 6-4. Carlos Alcaraz then eliminated Stefanos Tsitsipas in the evening.
The duel will take place at Roland-Garros on Friday afternoon. The 20-year-old Spaniard, who became the youngest world No. 1 when he won his first Grand Slam tournament last year at the US Open, inflicted 36 winning shots.