ARLINGTON -- Coming off one of the best starts in his young career, one in which he fanned a personal-best 10 batters, Brayan Bello took the mound on Wednesday afternoon seeking his 13th win of the season.

With Bello staked to an early four-run lead behind a three-run homer by Adam Duvall and a solo shot by Bobby Dalbec, it felt like the 24-year-old hurler was well on his way to another victory.

Then, in the blink of an eye, it all came crumbling down.

Bello -- and four Red Sox relievers -- got roughed up by the Rangers as Boston yielded 15 unanswered runs en route to a 15-5 loss at Globe Life Field.

“This was not a good one,” Red Sox manager Alex Cora said. “[Bello’s] command was off and they put some good swings on pitches in the zone. This is one of those where we have to turn the page and be ready for the next one.”

Bello, who flashed his dominance in a career-best 10-strikeout performance on Friday against Toronto, couldn’t seem to replicate that magic against Texas in an outing that was marred by inconsistency. His command eluded him on a day when he issued four walks, and when he was in the zone, the pitches were often center-cut, leading to plenty of line drives.

“To be honest, I don’t know what happened,” Bello said through Red Sox interpreter Carlos Villoria Benitez. “I tried to execute my pitches and get ahead of the hitters, but it just wasn’t my day today.”

Bello ultimately yielded a career-high eight runs on eight hits in just three innings. Most of the damage came in the bottom of the second inning when the Rangers blitzed the right-hander for six runs.

In that decisive frame, Bello allowed three extra-base hits, including back-to-back home runs to Jonah Heim and Mitch Garver.

“I think the Heim swing was a gut punch for us,” said Cora. “After that, we were unable to stop them.”

Bello noted that he did his best to make in-game adjustments to stop the bleeding, but he was simply outmatched by the Rangers' offense.

“I’ve never had a game like that before,” Bello said. “I felt like every pitch that I threw, they were able to square it up and hit the ball hard.”

Bello’s lackluster start against Texas continued a notable disparity between his efficiency in day and night games.

Bello is 9-5 with a 2.80 ERA in 17 night starts, but the right-hander has struggled mightily during day games, falling to 3-5 with a 6.94 ERA in 10 outings.

Despite the stark difference, Bello said that his pregame preparation for starts remains the same for both day and night games.

“I do the same work whether the game is day or night,” Bello said. “I try to do my routine and everything the same. How long the activation is and how the exercises are … it's the same. So, to be honest, I don’t know what’s going on with that.”

Bello has been battle-tested over the past month, as the matchup against the Rangers was his sixth consecutive start against an AL playoff contender. Over that stretch, Bello has faced the Astros (twice), Rays, Orioles, Blue Jays and Rangers.

Despite not always getting the desired results, Bello said that he gained valuable experience from such a challenging stretch, and he plans to grow from it.

“I’ve pitched against good teams in the past and have been able to learn a lot from those starts -- even today," Bello said. "So I’m just going to learn from what happened today and execute next time.”

Boston is certainly hopeful that Bello can improve from this season, as the young hurler projects to be an integral part of the rotation in the future.

“He’s a good pitcher,” Cora said. “He’s a part of the future and he’s a part of our present. He just had a bad one today.”