The United States baseball team gained some momentum heading into the medal round, recording a 4-2 victory on Wednesday over Japan in 11 innings for their fourth straight win.
The Americans, who finished the preliminary round in third place with a 5-2 record, took advantage of Olympic baseball's newest rule.
Starting the 11th with runners on first and second base with the score deadlocked at 0-0, Team USA received consecutive RBI singles from Brian Barden, Nate Schierholtz and Matt Brown.
John Gall added an RBI groundout to give the Americans a 4-0 advantage, and the Japanese managed just two runs in the bottom of the inning.
Five US pitchers combined for 10 scoreless frames, allowing just three hits and two walks with seven strikeouts in that span. Jeff Stevens, who tossed two scoreless frames, recorded the win.
"Like all of the teams, we have had our ups and downs," Stevens said.
"You come to the field and you are playing a quality team day in and day out. You try to come to the park, prepare and play as best as possible. We are looking forward to the medal round."
Hiroyuki Nakajima and Atsunori Inaba each drove in a run for the Japanese, who also had already secured a spot in the semi-finals - finishing fourth with a 4-3 record.
Next up for the United States are reigning gold medalists Cuba, who have won three of the four gold medals in the sport. Cuba used the new extra-inning rule to defeat the US 5-4 in 11 innings during the preliminary round.
Japan will face undefeated Korea in the semi-finals. The Japanese suffered a 5-3 setback to the Koreans in the preliminaries.
In other games on Wednesday, Giorbis Dubergel belted a grand slam to highlight a nine-run second inning and propel Cuba to a 17-1 triumph over China in a preliminary contest.
Michel Enriquez led the onslaught with four hits and three RBI, while Alexei Bell added three hits, two RBI and two runs scored for Cuba (6-1).
Six different Cuba players recorded at least two hits - including Ariel Pestano, who clubbed a two-run homer in the fourth.
Lei Li had an RBI single in the seventh for China (1-6), which has been outscored by a 60-14 margin.
In another contest, Daeho Lee belted a two-run homer in the first and Taekkeun Lee added a solo shot in the fifth as Korea cruised to a 10-0 triumph over the Netherlands.
Yongkyu Lee had four hits and Jongwook Lee added three hits to propel undefeated Korea (7-0).
The Netherlands (1-6) have been outscored by a 50-9 margin in the tournament.
Chih-Hsien Chiang delivered the game-winning RBI single in the 12th innings to lead Chinese Taipei to a 6-5 triumph over Canada in both sides' final preliminary game.
Che-Hsuan Lin collected three hits - including a two-run homer in the second - for the Taiwanese, who scored five runs in the first two frames and improved to 2-5.
Stubby Clapp homered for the Canadians (2-5), who lost five of their last six contests after routing China in their opener.