May 31 (UPI) -- U.S. Open champion Daniil Medvedev and 2021 runner-up Stefanos Tsitsipas were upset in the fourth round of the French Open on Monday, as Iga Swiatek and American Jessica Pegula advanced to quarterfinals of the women's draw.
Marin Cilic, the No. 20 seed in the men's singles draw, beat Medvedev of Russia in straight sets.
"It was an absolutely fantastic match from the first point until the last," Cilic said in his on-court interview. "I enjoyed the atmosphere. I enjoyed the night session. I played incredible tennis, one of the best matches of my career from start to finish."
The 2014 U.S. Open champion converted 5 of 7 break points and fired four aces and 33 winners in the win over the second-seeded Medvedev 6-2, 6-3, 6-2 in one hour and 45 minutes on Court Philippe-Chatrier.
Next, Cilic will face another Russian -- No. 7 Andrey Rublev -- in the quarterfinals. Rublev advanced Monday when No. 11 Jannik Sinner of Italy retired in the third set of their fourth-round match.