Christian Pulisic said he could not accept the performance of referee Kevin Ortega after the United States crashed out of the Copa America on Monday.

Having been beaten 2-1 by Panama in their second Group C match, the USA knew only a victory would do against Uruguay on matchday three.

However, they suffered a 1-0 defeat at Arrowhead Stadium, with Mathias Olivera netting a second-half winner that was allowed to stand despite replays appearing to show he may have been offside in the build-up.

It is the first time the USA have gone out in the Copa America's group stage since 2007, having previously made it further when invited to take part in 1995 and 2016.

Referee Ortega was seen refusing a handshake from Pulisic at full-time, and while the USA captain would not blame the official for his team's exit, he was infuriated by his performance.

"Honestly, I saw things that I've never seen before right in front of my eyes today, things that truly I can't believe," Pulisic said at a post-match press conference. 

"It's not why we lost; we're not out of this tournament because of officiating. But I've just seen things where I don't know what I'm looking at. 

"I don't know what they're calling. I don't know what he's… he gives no explanation. He's doing things that I just can't accept. He wouldn't shake my hand. It's normal, I guess."

While the USA's home campaign is over almost as quickly as it began, Uruguay will now face the runners-up from Group D – likely Colombia or Brazil – in the last eight.

On the opposite side of the knockout bracket to favourites Argentina, they are considered contenders to go all the way, but assistant Pablo Quiroga – who was on the sideline as Marcelo Bielsa served a one-match ban – feels they have work to do.

"I think at the beginning of the game we were not intense enough in the initial press," he said. "From there they were able to get the first pass with some comfort, and that prevented us from recovering the ball as we normally do. 

"When we fixed that, in the course of the game, the process went more towards what we wanted. The team did not lose its form against an opponent that has very good players and a lot of class."