Team USA's Triston Casas trots the bases Monday after hitting a three-run homer against Japan as Hideto Asamura watches. Japan came back to defeat the U.S. 7-6 in extra innings at the Tokyo Olympics.

Team USA's Triston Casas trots the bases Monday after hitting a three-run homer against Japan as Hideto Asamura watches. Japan came back to defeat the U.S. 7-6 in extra innings at the Tokyo Olympics. / AFP via Getty Images

Team USA's baseball squad lost a 7-6 nail-biter Monday to host nation Japan in extra innings, leaving the Americans with no room for error as they hope to play their way into the gold medal final.

Facing the tournament's only other undefeated team, the U.S. had been poised for a pivotal win after grabbing a 6-3 lead. But Japan fought its way back and then forced extra innings after tying the score 6-6 in the bottom of the ninth.

From there, the tension only built higher. Under Olympic rules, teams start extra innings with runners on both first and second base.

In the top of the 10th, the U.S. couldn't bring its two runners home after a strikeout, a fielder's choice to second and a flyout. In the bottom of the frame, Japan used a sacrifice bunt to advance the runners to second and third, setting up a game-clinching at-bat.

With former major leaguer Edwin Jackson on the mound for the U.S., Japan's Takuya Kai roped a sharp single to the right-field wall for a walk-off win at Yokohama Baseball Stadium. It capped a scrappy game in which both teams called on their bullpens early and each used at least six relievers.

Half of the U.S. scoring came from 21-year-old Triston Casas, a minor leaguer in the Boston Red Sox system who sent a looping three-run homer into the left-field seats in the fifth inning. The opposite-field shot was Casas' second home run of the tournament — after his right-field blast against South Korea on Saturday.

Both Japan and the U.S. had been 2-0 going into Monday's game. Despite the loss, the U.S. still has a shot at a gold medal. Olympic baseball's tournament system is a bit complicated, using a repechage format that allows the top-ranked losing team in late rounds still to vie for a spot in the final.

Many U.S. fans might not have known the word repechage before these Games, but they know the idea, thanks to the wild card system — the most well-known example in U.S. sports. By any name, the concept now represents the Americans' best hope to win gold.

U.S. baseball's next game will be at 11 p.m. ET Tuesday against the winner of an elimination matchup between the Dominican Republic and Israel. The loser of that game will be sent into the bronze-medal game.

If it wins, the U.S. will advance to a second semifinal against either Japan or South Korea — depending on which of those two countries win their own semifinal game, according to the Tokyo Olympics' official blog.

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