Josh Peter

USA TODAY Sports

RIO DE JANEIRO — The U.S. boxing team has improved to 15-0 — not its record in the ring, mind you, but its record for getting booed here at the Olympics.

That’s right. Booed in every single bout.

The sentiment grew even clearer Monday night when the crowd booed American Mikaela Mayer during her fight against Russian Anastasia Belyakova.

“This is new to me," said USA Boxing coach Billy Walsh, who is from Ireland and coaching the Americans in the Olympics for the first time. “I don’t know what the history is between yourselves and Brazil."

According to the U.S. State Department website: “The United States and Brazil traditionally have enjoyed robust political and economic relations. The United States was the first country to recognize Brazil's independence in 1822.”

But that didn’t stop the Brazilians from taunting U.S. goalkeeper Hope Solo with cries of “Zika.’’ Or targeting the U.S. women’s beach volleyball teams with the same jeers. Or booing U.S. sprinter Justin Gatlin before the 100-meter final.

But the hostility toward American athletes has been no less relentless at the boxing venue. Mayer, during her first-round victory against a boxer from Micronesia, said she was confused when she heard the crowd rooting for her opponent.

“I’m like, there’s no way there can be more people from Micronesia than America in this building right now," she said.

Then it became clear — the Brazilians were rooting against her and the rest of the American boxers. Even when the American was fighting a Russian.

Walsh said he has tried to use the crowd’s booing as motivation, telling his team, “Let’s try to quiet this crowd."

It’s been virtually impossible, though, even though the U.S. has compiled a 10-5 record. Because when an American boxer starts to land punches, the American fans break into chants “U-S-A, U-S-A,’’ triggering yet another chorus of boos that drowns out the American fans.

Walsh shrugged.

“It doesn’t really make a difference," he said. “At the end of the day, the crowd is not going to be hitting you. It’s the guy in the other corner."