ST. PETERSBURG -- For Brayan Bello, the most prized starting pitching prospect the Red Sox have had in years, Monday night’s sequel against the Rays at Tropicana Field was shaping up to be even tougher than his opening act last week at Fenway Park.

But after a rough first two innings, Bello displayed the type of mental toughness and fortitude that hadn’t been necessary for him in the Minor Leagues this season.

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In those first two innings of Boston’s 10-5 loss to the Rays, Bello put his team in a 5-1 hole.

By the fifth inning, the Red Sox had tied the game up. This wouldn’t have been possible if not for Bello’s key in-game adjustment which led to scoreless frames in the third and fourth to wrap up his second career outing.

“I tried to attack them with my two-seam fastball," Bello said. "And when I saw they were taking those pitches, I tried to adjust and went to the four-seam fastball, and that’s when it went better."

The more times Bello pitches in the Major Leagues -- and it’s unclear at this point when he will get his next chance -- the quicker he will make those adjustments.

“Obviously there’s a lot of growing, a lot of learning, and tonight was a great learning experience for him. But we were very pleased with the last two innings,” said Red Sox manager Alex Cora. “He gave us a chance to win the game.”

At Triple-A Worcester, the two-seamer had been perhaps Bello’s best weapon. The Rays knew that, because that’s how the scouting process goes in the Major Leagues.

That attention to detail at the highest level is what has been most eye-opening for the 23-year-old righty, who is the No. 3 prospect for the Red Sox, according to MLB Pipeline.

“I learned a little bit about the strike zone and about the hitters,” said Bello. “Every at-bat, they try to look for a specific pitch.”

It was easy to see what went wrong for Bello in the first inning. He hit the leadoff batter Yandy Díaz and then walked Ji-Man Choi. Giveaways like that almost never work out in MLB.

In the second inning, Bello again started by putting himself in trouble, this time by walking No. 7 hitter Luke Raley, a recent callup from the Minors.

That was part of a 42-pitch inning in which Bello was touched up for three runs.

If Cora had a rested bullpen and a healthy pitching staff, Bello probably would've come out of the game at that point.

But Cora didn’t have either. And the kid stayed in.

“It’s the big leagues,” Cora said. “Yeah we’ve got to protect him, but we’ve got to protect the rest of the staff. And where we were coming into the game, we were short in a sense. But we came back offensively and he got 12 outs.”

For Bello, those final six outs -- in which he faced only seven batters -- will allow him to take something good out of what could have been a very rough night.

“Yeah, I think I’m grateful for the confidence that Alex showed me to let me finish that inning," Bello said. "And having the opportunity to finish strong with those last two innings, it was big for me."

What does Bello need to do to have cleaner outings going forward?

“The pitch mix I think is going to help, and confidence, too,” said Cora. “It’s not that easy, but the talent is there. We know that. But he’s still learning how to pitch, he’s still learning how to use his fastball in certain spots. He has a good changeup, and in the two outings, he’s been erratic with it. But you see the potential, and he’s going to keep growing.”

Diekman on outing: ‘Embarrassing’
When the Red Sox roared back for two in the third, one in the fourth and another in the fifth to tie the game, it marked the second straight night they rallied back from four runs down. Unlike Sunday night, when they pulled out an 11-6 win over the Yankees, the Sox didn’t get the relief pitching required to pull out the victory this time.

The Rays took back the momentum when veteran lefty Jake Diekman had a tough sixth inning that included hitting leadoff batter Taylor Walls on the first pitch and giving up a go-ahead double to Díaz.

“It’s pretty embarrassing,” said Diekman. “It sucks. We had momentum all the way up to that point. To come in, hit a guy on the foot, give up a [hard] out and a seed double, yeah, it sucks.”

Diekman has pitched six times in July and has allowed at least one baserunner in all of them.

“It’s definitely mechanical,” Diekman said. “I think we know what part of the mechanics it is; we’re just working through it.”