It’s been a learning process to get to this point for Boston Red Sox starting pitcher Kutter Crawford.

But Crawford sure put the lessons he learned to good use.

The 28-year-old right-hander continued his stellar start to the season Monday in a 6-0 loss to the Cleveland Guardians at Fenway Park. He pitched 5 2/3 scoreless innings while allowing just two hits and no walks with six strikeouts.

Crawford doesn’t have a win or loss yet through four starts this season, but the number next to his record is worthy of plenty of buzz. Crawford owns a microscopic 0.42 ERA, which is third-best among all MLB starting pitchers — it trails only Paul Blackburn and Shota Imanaga, both of whom haven’t surrendered a run in three starts.

Red Sox manager Alex Cora sees the difference for Crawford, who posted a 4.04 ERA last season, coming in how he handles a lineup the deeper he works into a game.

“He worked hard in the offseason to maintain his stuff from pitch 75 to pitch 100. Something he didn’t do last year. He kind of like hit the wall around that part of the game,” Cora told reporters. “Now the fastball’s playing, the cutter is good, the split was OK.”

The Red Sox are still cautious with Crawford once he gets past the fifth inning, though. He has thrown over six innings in an appearance only once in his career and was lifted with two outs in the sixth inning against the Guardians despite being at 92 pitches.

“He was great,” Cora said. “We’re mixing and matching. So I felt right there bring in (Brennan Bernardino). They had to make a decision with the righty. Well, they did the decision and the kid hit the ball out of the ballpark. We’re just thinking ahead, not only obviously in that spot but the next inning. It just didn’t work out for us.”

Crawford really came onto the scene with the Red Sox during the 2022 season. He worked out of the bullpen and as a starter that year while soaking up all the information he could.

“I think he learned a lot toward the end of season of ’22 when he got hurt,” Cora said. “Staying in the dugout, talking to guys, talking pitching. He has a good feel and has good stuff.”

While there were plenty of questions surrounding Boston’s starting rotation entering the season, Crawford cemented his spot on the staff. He’s struck out 24 batters in 21 1/3 innings to go along with his minuscule ERA while also holding opponents to a .122 batting average.

Crawford certainly has made big strides and he did that by taking past lessons with him to the mound.

“So kind of taking what I learned from then to now,” Crawford told reporters. “Throwing strikes is huge, competing is huge and trusting your stuff, having conviction in your pitches. Previous starts I leaned on the sweeper, today I leaned on the cutter. I had convictions in those pitches today. I felt good with the cutter. Reese (McGuire) is back there clicking some buttons and we were just riding with that.”