Just when Australia thought it was safe to get back in the batter’s box, with Japan ace Tomoyuki Sugano on the bench and out of pitches, it ran into the buzz saw that is Kodai Senga.

It didn’t take long for Senga to display the tools that could make him a major weapon out of Samurai Japan manager Hiroki Kokubo’s bullpen. Senga threw two scoreless innings in Japan’s 4-1 victory over the Australians on Wednesday, earning the win in relief.

“I was throwing for strikes in the bullpen,” Senga said. “If I’m able to do that I’m fine.”

The 24-year old threw 32 pitches, 21 of them strikes. He struck out four and allowed one hit. He entered the game in the sixth with the score tied 1-1.

“Senga is a major league pitcher in my mind,” said Buck Martinez, who managed the Toronto Blue Jays from 2001-2002 and led Team USA in the inaugural WBC in 2006. Martinez is part of the MLB broadcast team for Tokyo rounds of the WBC.

“I think he can pitch in the major leagues right now. As a starter, I think he’s got the stuff to pitch. He’s got a good body, he’s got great velocity and he’s got maybe one of the hardest splitters I’ve ever seen.”

Senga blew a 155-kph fastball by Luke Hughes for his first strikeout, dropped a 135 kph forkball on former Tokyo Yakult Swallows outfielder Mitch Dening and dialed up a 151-kph heater to fan Stefan Welch, sending the trio down swinging. Senga struck out Allan de San Miguel swinging on a 134-kph forkball to start the seventh before getting two outs on ground balls.

“You’ve got to remember, we don’t see 96 (mph, 154 kph),” Australia manager John Deeble said. “I think he was up to 97. That’s tough to hit at any time. That’s tough to hit in the big leagues.”

Senga didn’t show many signs of nerves in his first WBC appearance, perhaps other than his first pitch against Hughes, which sailed high. There may have also been some nervous energy behind the fastball he eventually blew away Hughes with.

“I put a little too much on it,” Senga said. “But I felt good.”

Senga solidified his spot on Kokubo’s roster with the best season of his career in 2016 for the Fukuoka SoftBank Hawks. He was 12-3 with a 2.61 ERA and 181 strikeouts in 169 innings. Senga finished with a 3.12 fielding independent pitching average (FIP) and 1.05 walks plus hits per innings pitched. For his career, he’s 30-16 with a 2.45 ERA and 2.59 FIP in 275 innings.

As a starter, his fastball isn’t always quite as powerful as it was in relief on Wednesday, but has good speed. His average velocity in 2016 was 147.1 kph (fourth fastest in Japan), according to Data Stadium, and he topped out at 155.

In addition to his fastball, Senga throws a slider, curve, and the nasty forkball that’s a key part of his arsenal. Senga threw his forkball a little over 20 percent of the time last season and led Japan with a swinging strike percentage of 29.8 with it per Data Stadium.

“I think he is certainly major league quality,” Martinez said. “He’s got the best fastball we’ve seen in the tournament so far. I know the Australian hitting coach was saying to his hitters, ‘I’ve never seen a split-finger (fastball) pitched like that.’ ”

While his control has been known to go awry at times, he’s tough to handle when he’s got it all going.

Samurai Japan will be counting on that. Because of the WBC’s pitch limits starters can only go so deep, and Kokubo plans to task Senga with helping to get the game to the closer when he can.

“Senga is going to be our second pitcher,”Kokubo said.

Deeble said he thought his players approached Senga with a good game plan and had some good at-bats against him on Wednesday. He also called him one of the best in Japan.

“As I’ve said, Sugano is the best pitcher in Japan,” Deeble said. “Him and (Shohei) Otani are the best two pitchers in Japan. I think Senga is very close to them also.”