Two-time defending champions Japan narrowly beat Brazil and 2009 finalists South Korea were shocked 5-0 defeat by the Netherlands as the World Baseball Classic got off to an engrossing start on Saturday.
Star pitcher Wang Chien-ming also threw six shut-out innings as he led co-hosts Taiwan to a 4-1 victory over Australia on day one of the pool phase, being played in four countries over the coming week.
South Korea came into the tournament as favourites to top Pool B in Taiwan, but they managed only four hits against dominant Dutch pitchers Diegomar Markwell, Orlando Yntema, Leon Boyd and Mark Pawelek.
The result, despite "Gangnam Style" dancing by their enthusiastic fans, puts South Korea in danger of missing out on the second round, and under immediate pressure as they gear up to face Australia on Monday and Taiwan on Tuesday.
In Pool A, co-hosts Japan started with a win but it was a close-run thing for the team, missing their Major League stars, as they twice had to come from behind before beating Brazil 5-3 in Fukuoka.
Trailing 2-3 in the eighth, infielder Hirokazu Ibata levelled it at 3-3 with a single to the right field, and captain Shinnosuke Abe gained a game-winning run when he hit a grounder with the bases loaded for a 4-3 lead.
Nobuhiro Matsuda added another run to complete the scoring.
"I started the game on the bench because of my carelessness (knee trouble), but I took the chance in the best situation. I'd like to thank everybody who set up the situation," said captain Abe.
"The first game is always difficult, because everybody is a bit nervous, but our home fans helped us a lot."
Japanese head coach Koji Yamamoto said: "I thought of nobody but Shinnosuke in that situation. I felt he showed a strong will to win. He continued to play as a catcher, even though he has a knee problem."
"It was really tough. This is one of the severe international games. My players did their job very well towards the end of the game. This win gives us further motivation to do well tomorrow," added Yamamoto.
In Taichung, Major League hurler Wang was the hero for Taiwan as he shut out Australia in the first six innings to become the winning pitcher.
Captain Peng Cheng-min grabbed the home team's first run with a single in the first inning and then added a solo home run.
"Our infielders and outfielders all helped out today," said Wang, who was unable to secure a new contract with the Washington Nationals last year and is currently a free agent.
"Right now I am hoping to give my best to Taiwan. I am not thinking about getting a Major League contract at the moment," he added.
In Sunday's games in Asia, Cuba will play Brazil, Japan take on China, and the Netherlands face Taiwan.
Asia's second round starts in Tokyo next week, while pool games are also being played in Puerto Rico and the United States. The final round is in San Francisco later this month.