American Taylor Fritz upset two-time defending champion Stefanos Tsitsipas 6-2, 6-4 to reach the Monte Carlo Masters semifinals on Friday.
Second-seeded Tsitsipas was on a 12-match winning streak on the French Cote d’Azur, where he claimed his two Masters 1000 titles.
“I stuck to the strategy of pulling the trigger and not letting him dictate with his forehand,” the No. 8 seed Fritz said.
Tsitsipas broke back to 4-4 in the second set, but then Fritz broke his serve easily for 5-4 and closed out the match with an ace for a love hold.
Fritz will next face fifth-seeded Andrey Rublev of Russia, who beat German qualifier Jan-Lennard Struff 6-1, 7-6 (5).
The top two seeds have now been knocked out of the clay-court tournament following Novak Djokovic’s exit in the third round on Thursday.