Left-hander Shota Imanaga joined his Japan teammates in celebrating a thrilling World Baseball Classic semifinal victory over Mexico on Monday, but he remained fixated on what will be the biggest start of his career the following day.

Japan skipper Hideki Kuriyama has tapped the 29-year-old DeNA BayStars ace to take the mound opposite the United States in the deciding game of the WBC, pitting the defending champion Americans against the tournament's only two-time winners.

Japanese pitcher Shota Imanaga tries to get a feel of the mound on March 19, 2023, at loanDepot park in Miami, Florida, the venue of the World Baseball Classic final and semifinals. (Kyodo)

"I just couldn't stop thinking about my start in the final, so I believe I was the only one on the team who stayed nervous instead of erupting into celebrations," Imanaga said.

Tuesday's momentous start follows two relief appearances earlier in the tournament.

Imanaga relieved Yu Darvish and allowed one run in three innings against South Korea in a Pool B game on March 10. Six days later, he worked a scoreless inning against Italy in the quarterfinals.

The U.S.-Japan final could see the matchup the world has been waiting for between Los Angeles Angels teammates Shohei Ohtani and Mike Trout.

Regarding the potent U.S. lineup, Imanaga said, "I'll see what kind of pitch might work against each hitter. My team has so many great pitchers, so I'll pitch with the help of everyone."

With Japan's first WBC title since 2009 on the line, both Ohtani and Darvish could pitch in relief against the United States.

The Americans have scored 49 runs in six games through the semifinals. Trea Turner, batting ninth, has hit .368 with four home runs and 10 RBIs.

Last year in Japan's Central League, Imanaga had an 11-4 record with a 2.26 ERA in 21 games.

U.S. national baseball team members line up at loanDepot Park in Miami, Florida, on March 18, 2023, ahead of the World Baseball Classic quarterfinal game against Venezuela. (Kyodo) ==Kyodo

Related coverage:

Baseball: Murakami lifts Japan into WBC final vs. U.S.