The United States heads to its first men’s Olympic soccer tournament since 2008 off a performance it would rather forget.

Shota Fujio converted a penalty kick in the sixth minute, Mao Hosoya added a goal in the 69th and Japan won 2-0 in an under-23 game Tuesday night in the Americans’ last warmup match in Kansas City, Kansas.

“Since we started this process eight months ago, this was, I would say, the lowest performance by far that we had,” U.S. coach Marko Mitrovic said. “I strongly believe that this group can do much better than they showed today.”

Japan was awarded the penalty kick when Koki Saito flicked the ball off the right arm of defender Bryan Reynolds at the edge of the penalty area. Fujio sent the penalty kick to Patrick Schulte’s right as the goalkeeper jumped to the left.

Japan scored its second goal after intercepting John Tolkin’s throw-in. Shunsuke Mito dribbled toward the goal, and his pass deflected off defender Jonathan Tomkinson and Schulte then Hosoya tapped in the rebound from four yards.

“Obviously, it wasn’t the game that we wanted to end kind of this journey on going into the Olympics,” said American midfielder Paxten Aaronson, the younger brother of national team midfielder Brenden Aaronson. “The guys know that one game doesn’t define us.”

Japan midfielder Rihito Yamamoto was stretchered off in the 24th minute after getting hit flush in the face with a shot.

Schulte started in goal, with Reynolds at right back, Walker Zimmerman and Tomkinson in central defense and Caleb Wiley at left back. Tanner Tessmann, Aaronson, Duncan McGuire, Johan Gomez and Griffin Yow were in midfield, and Taylor Booth headed the attack.

Midfielder Gianluca Busio didn’t play after hurting an ankle while playing for Venezia in its playoff against Cremonese on June 2, when it earned promotion to Serie A.

The U.S. will open against Olympic host France on July 24 then will meet New Zealand and Guinea. Japan will play Paraguay, Mali and Israel.

Men’s Olympic soccer is limited to players under age 23, with each team’s 18-man roster allowed three players over the age limit. The 31-year-old Zimmerman captained the U.S. and was the only overage American player to dress.

Rosters of two goalkeepers and 16 outfield players must be submitted by July 3, and each team will designate up to four standbys, including one goalkeeper.

“The U.S. has never brought home a medal, and I think this team can do that,” Tessmann said.

Players spent part of their lead-up to Tuesday’s match in a challenging experience.

“We did a lot of escape rooms, to be honest,” Aaronson said. “Walker was kind of the team leader in that. We completed all of them — all six. So, yeah, it was crazy — six in two days, so our brains were working.”