PITTSBURGH -- Dane Dunning once again delivered a solid start for the Rangers, but a rare quiet night of offense and familiar issues with the bullpen led to a 6-4 loss to the Pirates in the series opener at PNC Park.

Though it was rarely as easy as 1-2-3 for Dunning, he was able to manage traffic on the basepaths with relative ease. He allowed nine runners to reach base on six hits and three walks, but he allowed only one to come home in the second, which Ke’Bryan Hayes led off with a first-pitch double then scored on Connor Joe’s groundout.

The traffic equated to extra pitches for Dunning, who was unable to make it through six innings after issuing a two-out walk and a two-out single in the sixth.

“They were really good at not chasing stuff off the plate,” Dunning said. “I just made some elevated sliders they were able to put some good swings on and some elevated mistakes.

“I thought they had a good approach at the plate. We kind of just took how their approach was and tried to do the opposite later on.”

With a pitch count of 97, Dunning was lifted by manager Bruce Bochy for righty Josh Sborz, who ended the inning with a strikeout. But after the pitchers weathered two-out baserunners in five of their first six innings, the problem came back to bite in the seventh. Sborz allowed a single and a walk to bring up Carlos Santana.

“Sborz comes in and just makes great pitches to help Dane out. We were at the finish line there for him,” Bochy said. “Then he lost it. He had two outs and nobody on, and lost the feel of it.”

Even without the feel he demonstrated early, Sborz nearly got out of it, when Adolis García threw a 95.4 mph dart home on Santana’s single to right field. The ball got home in time to give Jonah Heim a chance to nab Bryan Reynolds and keep it a one-run game, but the Pirates challenged the initial safe call and it was overturned.

“It’s a game of inches,” Bochy said. “Bang-bang play, we’re off the field but it gets overturned, because he did beat it by just a few inches.”

Sborz gave way to Joe Barlow, who began his outing by walking Hayes on five pitches to load the bases. He got two strikes on Tucupita Marcano, but he hung a slider that Marcano lifted into the center-field shrubbery at PNC Park for his first career slam.

With a rare night of struggles for arguably the best offense so far this season, the Rangers were put in a hole too deep to dig out of, though Josh Jung’s two-run homer off David Bednar -- one of the game’s best closers this season -- provided a little momentum in the ninth.

And had the game of inches been flipped in the other direction, maybe it would have been the story of the night.

But instead, it was the Rangers’ bullpen. It’s no secret the unit has been the area of the team’s game that needs the most improvement. Texas relievers entered the game with a collective 4.57 ERA, the sixth-worst mark in the Majors. The rotation going deep has helped Bochy not have to turn to the bullpen for heavy innings very often; entering Monday, the ‘pen had thrown 147 2/3 innings, which was the least of any MLB team.

“We’ve got to have somebody step up,” Bochy said. “I don’t know what else to say, but that’s what we’re doing, is trying to get these guys on track. … We’ve got to get this thing in order, because we’re a team that scores runs, but we’ve got to find a way to win some of these close ones, too.”

If there’s anyone who knows what the Rangers’ relievers have done behind the scenes to try to forge a new path, it’s Dunning. He began the season in the bullpen as a multi-inning threat before stepping up in place of Jacob deGrom and giving the team strong start after strong start.

“I know the work that they put in every day. I was a part of it, and I see it. They’re a bunch of grinders,” Dunning said. “They go out there and do their jobs to the best of their abilities. I think they’re an extremely talented bullpen. Tomorrow’s a new day.”