July 31 (UPI) -- Nick Martinez allowed just four hits and one run over five innings to lead Team USA to a 4-2 win over South Korea in its final group stage game at the 2020 Summer Games baseball tournament Saturday in Yokohama, Japan.
The win clinched the top seed in Group B, which means the Americans are exempt from the first round of the knockout round of the double-elimination tournament.
First baseman Triston Casas went one for four with a two-run homer in Saturday's win. Designated hitter Tyler Austin and shortstop Nick Allen also drove in runs for Team USA.
Martinez issued nine strikeouts and no walks in his 87-pitch effort.
South Korea got off to a hot start. Center fielder Hae Min Park and right fielder Jung Hoo Lee started the game with back-to-back singles. Park scored when left fielder Hyunsoo Kim reached base on a fielder's choice in the next at-bat.
South Korea starter Ko Young-pyo did not allow a hit for the first two innings. Team USA then rallied for two runs in the bottom of the fourth.
Young-pyo hit second baseman Eddy Alvarez with a pitch in the first at-bat of the half-inning. He then struck out designated hitter Tyler Austin, which prompted Casas to step into the box.
The Team USA first baseman reached down and swatted a 2-2 offering over the right field fence for a two-run homer.
Allen added to the lead with a solo homer to left field in the bottom of the fifth. Austin plated left fielder Jamie Westbrook with an RBI single three at-bats later for Team USA's fourth run.
South Korea first baseman Jaeil Oh plated the game's final run with a sacrifice fly in the top of the ninth.
Team USA battles Japan in the second round of the knockout round Monday. Japan claimed the top seed from Group A with a 2-0 record, which included a 7-4 win over Mexico on Saturday in Yokohama.