BOSTON -- This wasn’t supposed to be how it would go for Brayan Bello.

Not when he signed a six-year, $55 million contract extension three weeks before making the first Opening Day start of his career. Despite the faith the organization put in him with the contract and the Opening Day nod, the 25-year-old isn’t a finished product.

And that was again evident on Friday night when he got roughed up by the Yankees -- the team he had dazzled to the tune of a 1.45 ERA against in five previous starts.

In the first matchup between the rivals this season, the Red Sox and Bello took an 8-1 loss at Fenway Park.

After getting touched up for six hits and five runs (four earned) over 4 2/3 innings in which he walked three and struck out five, Bello’s ERA through 12 starts this season is 5.00.

Through 12 starts in 2023, he had a 3.27 ERA and was considered the ace of the staff. That distinction now belongs to Tanner Houck.

What is separating Bello from being the pitcher he was for most of last season?

“Strike throwing,” said Red Sox manager Alex Cora. “I think that's the most important thing. It happened in the last outing. The walks put him in a bad spot. Today, it was a weird one. Stuff-wise, it was good, but we have to be more aggressive in the zone.”

Considering the events of his last start, when Bello gave up a grand slam to Gavin Sheets to snap a 1-1 tie and threw his glove down in disgust, a bounce-back outing was the righty’s clear mission.

But it wasn’t to be. Alex Verdugo, Bello’s former teammate, smashed a two-run homer to center to open the scoring in the top of the first.

"I've obviously seen him pitch a lot. I understand what pitches he throws, what he likes to throw. I've never faced him at all before,” Verdugo said. “So I'm really just trying to get out over, see something, and I got a good pitch to hit."

The run that Bello allowed in the fourth never should have happened. On a feed from first baseman Dom Smith that should have been the third out of the inning, Bello dropped the throw for an error and an unnecessary add-on to the Yankees' lead.

Instead of regrouping in the fifth, Bello gave up a leadoff single to Anthony Volpe, who then stole second and third against him. Aaron Judge drew a one-out walk and Verdugo then became an annoyance again, ripping an RBI double off the Monster.

“We weathered the storm [after Verdugo’s homer], we were right there in the game,” Cora said. “We missed a play at first, we let Volpe steal third in a big situation. I think we’ve just got to be better at throwing strikes, too. That’s the most important thing.”

Bello is searching for answers and still feels the quality of his pitches isn’t translating into results.

“I think my stuff was better than last start,” Bello said. “I feel like my sinker, my changeup and my slider were working well today.”

The issue seems to be mindset, a lack of location or a combination of both.

“My pitches all have a lot of movement so for me to try to control them that’s a challenge,” Bello said. “When I try to control those pitches, I sometimes leave them in the middle, and that’s when the battles start. So for me, I just need to be better trying to have a better location with the pitches.”

“We were talking about getting ahead, staying ahead, and I don't think that was the case,” Cora said. “He fell behind to nine hitters, and six or seven of them got on base. They have a good offense, but with that, we have to be more aggressive in the strike zone.”

Bello agreed that the aggression he used to his advantage last season has been lacking, for whatever reason.

“I need to be more aggressive,” Bello said. “I need to be attacking the hitters in the fourth, fifth and sixth innings. I think that’s something I’ve been missing the past few starts.”