The South Korean bats started off hot before cooling off considerably in a deflating 8-6 loss to Japan at the World Baseball Classic on Saturday.

The first three South Korean batters of the game each hit a single off starter Yusei Kikuchi, with Lee Jung-hoo capping that run with an RBI knock to left.

Three batters later, Moon Bo-gyeong, an offensive hero with a grand slam in the team's 11-4 win over Czechia on Thursday, delivered a two-run double to center to give South Korea a 3-0 lead.

Kim Hye-seong of South Korea celebrates after hitting a two-run home run against Japan during the teams' Pool C game at the World Baseball Classic at Tokyo Dome in Tokyo on Saturday. (Yonhap)
Kim Hye-seong of South Korea celebrates after hitting a two-run home run against Japan during the teams' Pool C game at the World Baseball Classic at Tokyo Dome in Tokyo on Saturday. (Yonhap)

South Korea pitchers couldn't make the lead hold up, however, as Japan hammered four home runs over the first three innings to grab a 5-3 lead.

South Korea punched back to tie the game at 5-5 in the top fourth, thanks to a two-run home run from an unlikely source -- No. 9 hitter Kim Hye-seong.

Facing reliever Hiromi Itoh, Kim turned on an inside fastball and deposited into the seats in right-center field. The ball traveled 410 feet, two feet farther than a blast by Kim's Los Angeles Dodgers teammate, Shohei Ohtani, in the bottom third.

However, after Kim's home run, South Korea was held without a hit over the next three innings.

Itoh struck out four batters in the fifth and sixth, and new pitcher Atsuki Taneichi struck out the side in the seventh.

Lee Jung-hoo of South Korea celebrates after hitting an RBI single against Japan during the teams' Pool C game at the World Baseball Classic at Tokyo Dome in Tokyo on Saturday. (Yonhap)
Lee Jung-hoo of South Korea celebrates after hitting an RBI single against Japan during the teams' Pool C game at the World Baseball Classic at Tokyo Dome in Tokyo on Saturday. (Yonhap)

South Korea showed a little bit of life in the eighth against Yuki Matsumoto, with Lee Jung-hoo opening the inning with a double and Kim Ju-won delivering an RBI single.

South Korea then loaded the bases with two outs in the same inning, but Kim Hye-seong couldn't come through this time, as he struck out looking against Matsumoto.

It ended up being South Korea's final rally.

South Korea struck out 15 times in the loss, including three each by cleanup hitter Ahn Hyun-min and Park Dong-won.

Kim Hye-seong said after the game he could only remember his eighth-inning strikeout, not his game-tying home run.

"I should have taken a swing there," Kim said. "I thought the sinker was going to drop a little more but it ended up being a strike. It was my mistake."

When told South Korea still put up a good fight against the defending champion, Kim said, "This is devastating. It's never a good thing when you lose." (Yonhap)

South Korean players leave the field after losing to Japan 8-6 in their Pool C game at the World Baseball Classic at Tokyo Dome in Tokyo on Saturday. (Yonhap)
South Korean players leave the field after losing to Japan 8-6 in their Pool C game at the World Baseball Classic at Tokyo Dome in Tokyo on Saturday. (Yonhap)