Tennis fans loudly booed the mayor from the minute he was announced through his praise of Arthur Ashe Stadium's brand-new roof and into his remarks about a player he planned to root for, according to video of the event and social media.
During his remarks, de Blasio told the crowd "a lot of New Yorkers are going to be rooting for Puerto Rico's own Monica Puig, we are so proud of what she achieved in the Olympics."
But the recent gold medalist had been eliminated from the tournament earlier in the day, losing in the first round to China's Zheng Saisai.
Lol. Bill de Blasio is talking about cheering for Monica Puig here when she already lost. He is never aware of anything. #USOpen— Christian (@ItsMeCree_) August 29, 2016
The mayor may be used to The Bronx cheer in Queens. He's been booed on every Opening Day at Citi Field since he's taken office.
A spokesman for the mayor, Eric Phillips, said getting booed is a "time-honored tradition if there ever was one" in New York City.
When asked about the Puig flub, Phillips said he didn't "understand the question."