Ohtani, the reigning National League MVP in MLB, was the match-winner for Japan in the 2023 final, striking out his then teammate Mike Trout of the USA to win the crown in the final.
He lit up the Tokyo Dome in their first match of the tournament as the team's designated hitter, going 3-4 in his at-bats, including a grand slam in the second inning. His team would record 13 hits in a game that was never really a contest.
His LA Dodgers teammate, Yoshinobou Yamamoto, was also at the fore, pitching 2.2 scoreless innings against a Chinese Taipei outfit that struggled all game long.
It was always a tall order for Chinese Taipei to go toe-to-toe with the juggernaut of Japan. Not only had they lost their opener to Australia 3-0 on Thursday, but the 2023 champions brought a roster full of talent from home and the MLB - it didn't take long for them to flex their muscles.
On the very first pitch of the game, global superstar Ohtani smacked a line drive into the right-field corner for a double. He would be moved over to third by Kensuke Kondo, but Chinese Taipei's starting pitcher Hao-Chun Cheng got out of the jam - this would be the best it got for him.
After a hitless bottom of the first, thrown by 2025 World Series MVP Yamamoto, Japan would unleash in the second inning.
A walk, a single from Shugo Maki and a hit by pitch would set the table for Ohtani, who duly delivered. He hit a curveball from Cheng out of the park, despite having to reach for it, to send the Tokyo crowd into a frenzy.
The damage didn't stop there for the visitors. Japan would bat around to Ohtani again, who hit a stinging single into right field, meaning he was just a triple short of the cycle and five RBI before Chinese Taipei had recorded six outs.
In the WBC, a game can be 'mercy ruled' after five innings if a team is 15 runs ahead. As the third inning started, Japan already had 10 runs, and looked good to keep adding to their already unassailable lead.
With the house band rumbling on in the background, new Toronto Blue Jays signing, Kazuma Okamoto, dumped a single into left field to bring in Seiya Suzuki of the Chicago Cubs.
Two more runs were then driven in by Sosuke Genda to make it 13-0 at the midpoint of the third.
At this stage, after more than an hour of play in the Japanese capital, Yamamoto had thrown just 31 pitches, whilst the Chinese Taipei pitching staff had sent down 97.
Despite the deficit, they did show some fight loading the bases against Japan's starter, which would see him exit the game giving away no hits, with two strikeouts, but walking three, in his first meaningful outing of the season.
Shoma Fujihira would get his side out of the situation with a strikeout, allowing the batters to go back to work.
Japan were unable to end the game after the fifth or sixth inning with the score at 13-0, and there would be some cheer for Chinese Taipei as Yu Chang, a hero for his side three years ago, recorded their first hit of the encounter with a loopy single into right field.
They would not score from that, and the game would end in the seventh inning via the mercy rule, as Chinese Taipei were unable to get the three runs they needed to keep the deficit below 10 runs.
Both teams are back in action Saturday. Chinese Taipei have their most winnable game of Pool C when they face the Czech Republic from 04:00 CET, whilst Japan face their biggest test in Tokyo as they take on South Korea at 11:00 CET.
Friday is the first 'full' day of play at the WBC, with action getting underway in North America this evening - follow it all with Flashscore.