Gregg Berhalter hit out at a "silly" mistake from Timothy Weah after his red card in a 2-1 defeat to Panama put the United States' place in the Copa America at risk.

Having opened their home campaign with a 2-0 win over Bolivia, the USA slipped to a surprise defeat in their second match in Atlanta, leaving them likely needing a result against Uruguay on matchday three to progress.

The tournament hosts played over 70 minutes with 10 men after Weah lashed out at Amir Murillo, and they were unable to force a late equaliser after Adalberto Carrasquilla also saw red for Panama.

After the game, Berhalter said Weah's actions were costly but also suggested Salvadoran referee Ivan Barton was always poised to make a big decision.

"We talked beforehand about the tendencies of this referee, we knew what he's capable of and to be honest I think we played right into his hands," Berhalter said. 

"We made that decision pretty easy. Tim got bumped, he got checked and he reacted.

"He apologised to the group and he understands what a difficult position he put the group in.

"Nonetheless, it happened and as a result we lost this game and we're going to have to move on and figure out how to win the next game.

"The guys dug in and we were close to coming out with a point. But it's a shame, because there was more in this game, and a silly decision by Timmy leaves us short-handed."

Forward Christian Pulisic echoed his coach's sentiments, saying: "Timmy knows the mistake he made. 

"That's it. He's going to learn from it. It sucks. It's not the way you want to put your team in that position. 

"It hurts. Just the minimum, it's a lapse of judgement. It's just one simple second, you respond to something."