A fastball up and off the plate to Guardians left-handed hitter Steven Kwan was an inauspicious beginning to Dodgers right-hander Roki Sasaki’s season debut.

The arm-side miss fell in line with a persistent spring-training pattern for Sasaki, who struggled with command from his first Cactus League start through his Freeway Series appearance last week.

Over the course of a seven-pitch strikeout, however, Sasaki adjusted — something he failed to do during game action this spring.

“I actually didn’t have confidence at all before this game started,” Sasaki said through an interpreter Monday. “But I was just focusing on doing what I can control.”

In the Dodgers’ 4-2 loss Monday, Sasaki’s first start of the season was something of a best-case scenario. He held the Guardians to one run and four hits in four-plus innings. And the biggest difference from his spring training struggles was he issued just two walks.

The Dodgers squandered the effort with a lack of offense, in their first loss of the season.

Sasaki will have more to prove against stronger offenses than Cleveland’s. But his performance at least suggested that the Dodgers’ faith in him wasn’t misplaced.

“We know he can do it here, and especially now that his velocity is back to closer to where it used to be,” Dodgers general manager Brandon Gomes said last week. “I feel like he puts us in a great position to win.”

Dodgers manager Dave Roberts removes starting pitcher Roki Sasaki from the game.

Dodgers manager Dave Roberts removes starting pitcher Roki Sasaki from the game in the fifth inning Monday against Cleveland.

(Ronaldo Bolanos / Los Angeles Times)

The Dodgers had seen Sasaki bounce back before. He had a middling start to last season and pitched through shoulder discomfort before landing on the injured list last May. His average fastball velocity plummeted from 98 mph in his MLB debut to 94.9 mph in his last start.

He returned from the IL in time for two relief appearances in September, his fastball sitting above 99 mph, and a dominant postseason run. He didn’t allow a run in eight of his nine playoff outings, and he posted a 0.84 ERA.

“He could have cashed in last year,” manager Dave Roberts said before the game. “Given his health early, the lack of performance towards the middle of the year, towards the end he could have just written it off and started fresh in the offseason.

“But he was willing to pitch out of the bullpen, ramp back up and give us whatever we needed. So for me, that was something where he put himself out there. That’s why I have a lot of confidence right now [that he can] turn the corner from spring training.”

Sasaki still threw some non-competitive pitches Monday. That inefficiency brought his pitch count up to 78 pitches twice through the Guardians’ batting order, and Roberts pulled him when the lineup turned over again.

Sasaki also reigned in his misses, used both sides of the plate, and effectively deployed his new cutter as a put-away pitch early.

“I couldn’t get through five innings, but the results overall felt pretty good,” Sasaki said. “I kind of have confidence about that.”

Through the first two innings, Sasaki held the Guardians scoreless, and to just one bloop single. But in the third, he threw a four-seam fastball down the middle to Austin Hedges and hung a cutter to Kwan for a pair of doubles and a run.

Dodgers outfielder Kyle Tucker rounds second base after a Mookie Betts double during the ninth inning.

Dodgers outfielder Kyle Tucker rounds second base after a Mookie Betts double during the ninth inning against the Guardians at Dodger Stadium on Monday.

(Ronaldo Bolanos/Los Angeles Times)

Next, Sasaki walked Chase DeLauter, and the inning threatened to spiral. But Sasaki locked in to strike out José Ramírez and induce Kyle Manzardo to line out, escaping without further damage.

With no outs and one runner on in the fifth inning, Sasaki handed the ball over and left-hander Tanner Scott took over. Dodgers fans sent Sasaki, who’d been booed during his last spring start, off with a warm ovation.

“I think it should be a big boost to his confidence,” Roberts said after the game. “… When you don’t have success, it’s hard to have real confidence. That was certainly an honest admission. But when you perform, you start to have true confidence. So hopefully he can build on this one.”

After Scott, Dodgers left-hander Justin Wrobleski, who is in line to join the rotation when the schedule isn’t so packed with off days, provided four innings. He gave up three runs, all in the seventh.

The Dodgers didn’t score until the final inning, with the help of a little luck. Kyle Tucker reached base on a chopper that squeaked through the infield and then advanced all the way to third on a wild pitch. Mookie Betts then drove him in with a line-drive double. Two batters later, Betts scored as Freddie Freeman grounded out to first.

“The takeaway is, we’re 3-1 and the guys that we expect to swing the bats aren’t swinging the bats right now,” Roberts said. “So that’s a good thing; they’ll hit.”