It was an odd quarterfinals match at the French Open between Carlos Alcaraz and Stefanos Tsitsipas Tuesday.

Alcaraz blew Tsitsipas out in straight sets — 6-2, 6-1, 7-6 — leading many to wonder what was wrong with Tsitsipas. Alcaraz is the world’s No. 1-ranked tennis player, but Tsitsipas is at No. 5. 

A better match was expected even with Alcaraz the favorite. 

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Tsitsipas has a reason why he looked sluggish Tuesday. 

"One thing that I’m going to try to avoid in the future is to have melatonin pills [sleeping pills] and naps before matches because it clearly doesn’t seem to be working," Tsitsipas told reporters, via multiple reports. 

The French Open follows the same time frame as the U.S. Open in that night matches become more common as the bracket approaches the finals. Because of that, some players like to refresh with naps prior to their matches, which we’ve seen go past midnight. 

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That seems to have hindered Tsitsipas, who couldn’t get himself to his usual game readiness. 

"I had some late-night sessions. Not super late, but late enough for me to kind of have my sleep schedule ruined, in a way," Tsitsipas explained.

"Sleep is a very vital, important thing, and recovery is the most important thing when competing and playing big slams like this."

However, Tsitsipas didn’t want to diminish what Alcaraz did on the court, calling his performance "great."

"I just wish it never happens again. It sucks," Tsitsipas said. 

With the victory, Alcaraz advances to the semifinals to face Novak Djokovic, who ranks No. 3. 

The match will be played at 8:45 a.m. ET Friday.