A spectator at the U.S. Open was removed early on Tuesday after Alexander Zverev, a player from Germany, told the umpire that he had heard the man say a phrase associated with the Nazi regime, according to a spokesman and a video of the encounter.

The disruption occurred in the fourth set of the match between Zverev, the No. 12 seed, and sixth-seeded Jannik Sinner of Italy at Arthur Ashe Stadium in Queens. Zverev was serving at 2-2 when he paused and approached the umpire.

“He just said the most famous Hitler phrase there is in this world,” Zverev told the umpire, according to video of the encounter. “It’s unacceptable.” The umpire, James Keothavong, turned toward the stands and asked the man to identify himself, but he did not.

“We’re going to get him out,” Keothavong said, then urged fans to remain fair and to show respect to both players.

Nearby, spectators pointed the man out to officials and security personnel, who approached the man. He got up from his seat and left the stands at the stadium, videos posted to the social media platform X showed.

Chris Widmaier, the spokesman for the U.S. Tennis Association, said on Tuesday that a “disparaging remark was directed toward Alexander Zverev. The fan was identified and escorted from the stadium.”

Zverev elaborated on the man’s comments after the match, saying, according to The Associated Press: “He started singing the anthem of Hitler that was back in the day. It was ‘Deutschland über alles,’ and it was a bit too much.”

It was not immediately clear what consequences, if any, the spectator would face.

Originally written in 1841 as the “Song of the Germans,” the piece was adopted as the national anthem in 1922. The opening verse, including “Deutschland, Deutschland über alles” (“Germany, Germany, above all else”), was misused after 1933 by the Nazis to try to give legitimacy to their expansionist war aims, according to a German Parliament history page.

The phrase came to be seen as sinister, and the anthem was banned after World War II then reintroduced with that phrase and verse removed.

Zverev beat Sinner in a match lasting four hours and 41 minutes. It was the longest match at the U.S. Open so far this year, the organization said on Tuesday.