TOKYO — It lasted just three innings. It included a grand total of 56 pitches. And it was nowhere near a flawless introduction to Major League Baseball.

But did Shotgun Roki ever put on one heck of a show.

Making his MLB debut Wednesday night, in front of his home nation at a sold-out Tokyo Dome and under immense pressure that had been building ever since his mid-January signing, Roki Sasaki ran the full gamut of emotions in the Dodgers’ 6-3 win over the Chicago Cubs, enduring the kind of twists and turns that will likely define his rookie MLB season.

There was jaw-dropping stuff — from 100-mph fastballs to helplessly unhittable splitters and sliders.

There was also wildly inconsistent command — leading him to walk five of the 14 batters he faced and miss the zone on well more than half of his pitches.

There were highlight-reel moments — like when he blew Seiya Suzuki away for his first career strikeout, and stranded the bases loaded in the third on back-to-back punchouts of Michael Busch and Matt Shaw.

And then there were expected examples of Sasaki’s inevitable growing pains — from his inability to slow the running game, to the bases-loaded free pass he issued to Kyle Tucker that resulted in his only run given up in his three-inning outing.

Welcome to the Roki Sasaki experience, one that should make the 23-year-old right-hander one of the most interesting players to watch on this year’s Dodgers team, if not all of baseball.

With the explosiveness of a 12-gauge, he can overpower opposing hitters with what Dodgers coaches already describe as an ace-caliber arsenal. But, with the precision of a sawed-off double-barrel, his performance can also be scatter-shot and impossible to predict.

“When you get youth and talent, which is Roki, what that introduces is variance,” manager Dave Roberts said. “So there’s going to be some really high highs, and then some things that you just don’t know that are gonna happen, because of his inexperience.”

The good news for the Dodgers: Sasaki’s inexperience didn’t derail Wednesday’s debut, with the young pitcher working out of just enough trouble to help lift the team to a two-game Tokyo Series sweep of the Cubs.

Roki Sasaki yells after striking out the Cubs’ Matt Shaw to end the third inning and escape a bases-loaded jam.

“He made some big pitches for us,” Roberts said. “At the end of the day, his talent, his compete, showed through.”

In the first inning, Sasaki was flawless. He lit up the radar gun with fastballs of 100, 100, 100 and then 101 mph to begin the night. He pumped 99-mph heat past Suzuki to record his first career K. He retired the side in order while a captivated Japanese crowd roared in applause.

“Being able to pitch in this special and excellent environment that the Japanese fans created for me was really great,” Sasaki said through an interpreter afterward. “I think it was a really good thing that I was able to pitch with a good nervousness.”

From there, however, the nerves seemingly started to get to him.

Sasaki lost fastball after fastball to his arm side in the second inning, issuing walks to Busch and Dansby Swanson before getting a reprieve on Pete Crow-Armstrong’s line-out double play. He started spraying the ball again in the third, following Jon Berti’s one-out single — the only hit Sasaki yielded in his outing — with three straight walks to force in a run.

At that point, the Dodgers still had a 3-1 cushion, thanks to a two-run rally in the second inning and a solo home run from Tommy Edman in the third. They’d add more insurance later in the game on a two-run home run from Kiké Hernández in the fourth and, to the raucous delight of the Tokyo Dome crowd, a Shohei Ohtani solo blast in the fifth.

But in this moment, with Sasaki seemingly on the ropes, Roberts got his bullpen active while staring toward the mound with a contemplative gaze.

It felt like, with Sasaki’s pitch count climbing quickly, he was likely down to his final couple batters.

“Even though my command went awry a few times during the game, I felt good about my mechanics and my delivery,” Sasaki said. “I just wanted to make sure that I can repeat it better going forward.”

In the next two batters, he provided a perfect template as to how.

Facing Busch again, Sasaki painted the outer edge with three high-velocity fastballs, ringing the former Dodgers infielder up on the last one for a strikeout looking.

With two outs, Sasaki got ahead of Shaw with a first-pitch heater at the knees for a strike, one of just three first-pitch strikes he registered in his outing. Then, he snapped off a couple low sliders — an important third pitch he has been working on improving this spring — that induced an inning-ending strikeout and stadiumwide sigh of relief.

“What was really impressive was the fact that he was able to bear down in that third inning and get a couple of huge strikeouts to end the threat,” Edman said. “There’s not many guys in the league that have stuff as good as he does.”

The quality of that stuff, pitching coach Mark Prior said before the Dodgers left for Japan, is already at the level of a big league ace. His signature splitter, in particular, was repeatedly lauded coming out of spring camp.

“The unique thing about his split-finger, it’s very unpredictable,” Roberts said pregame, mimicking Sasaki’s forkball-like grip in which the ball is shoved deep between his right middle and index fingers. “It can go to the left, it can go straight down, and it can go to the right. Roki doesn’t even know what it’s going to do.”

The challenge will be executing it, along with all his pitches, on a consistent basis during an already grueling transition to life in the majors.

On Wednesday, for example, too many of Sasaki’s splitters were what Roberts called a “ball out of hand,” starting so far out of the zone the Cubs weren’t tempted to chase. When coupled with his lack of control or ability to hold runners at first base — twice, the Cubs stole second with ease — each of his final two innings threatened to go off the rails.

“The arm talent is there,” Prior said earlier this month. “But we got to polish it up and keep developing him as a pitcher.”

“When he’s not commanding it,” Roberts added, “it gets a little bit tricky.”

This, however, is what the Dodgers signed up for, knowing there will be a learning curve in Sasaki’s path to becoming a finished product.

For now, he is uber-talented, but also uber-volatile.

It should make for intriguing viewing — and, the Dodgers hope, steady progress over the course of the season. So, it’s probably safe to get used to Shotgun Roki. Spectacles like Wednesday are bound to happen again.