YOKOHAMA, Japan (AP) — Red Sox prospect Triston Casas hit a go-ahead, two-run homer in the fourth inning, Nick Allen also went deep and the United States rallied past defending champion South Korea 4-2 to finish the group stage of the Olympic baseball tournament with a 2-0 record.
Nick Martinez, who left the major leagues for Japan after the 2017 season, struck out nine in five innings.
Scott McGough, Edwin Jackson, Anthony Gose and David Robertson finished a five-hitter for the Americans, who struck out 14.
The United States plays Japan on Monday night in the start of a double-elimination second stage.