Christian Pulisic said he was disappointed in his own performance following the United States' 4-1 loss to Belgium in the World Cup round of 16, an exit that saw him depart early with injury.

The AC Milan forward was substituted in the 59th minute after suffering a right ankle injury, replaced by Sebastian Berhalter. Pulisic went down in visible pain after a challenge with Belgium's Youri Tielemans, though no foul was called.

"I just totally twisted my ankle and my knee in one play," said Pulisic. "I mean, whatever. I have time to rest. It's just unfortunate way to finish."

The injury marked Pulisic's second of the tournament. He also battled a calf issue after a strong start against Paraguay, ultimately finishing the World Cup without a goal and just one assist.

"I felt really good this summer with the guys and I thought my level was high," said Pulisic. "Yeah, it's disappointing. I didn't quite have the moments I was hoping to and to try to help us to really push and get over this next step of beating a really good team.

"I'm disappointed with myself, of course, but I'm going to try to stay positive. I did a lot of good things and the team did as well."

Belgium advanced behind two goals from Charles De Ketelaere and one each from Hans Vanaken and Romelu Lukaku. Malik Tillman scored the lone U.S. goal in the defeat.

Pulisic credited Belgium's tactical approach rather than a lack of effort from his own team.

"Belgium had a good game plan and they played balls in behind us when we pressed and caused a lot of problems," said Pulisic. "Won a lot of second balls and they were good in the boxes. That's what it comes down to and they were clinical."

Pulisic said he plans to rest before returning to preseason training with AC Milan under new manager Ruben Amorim.