PITTSBURGH -- In the short term, the Pirates’ 9-2 win over the Cubs on Tuesday night was a relief. They went into the sixth inning being no-hit by Kyle Hendricks, then all of a sudden, they were batting around in a seven-run seventh. In the end, they snapped a nine-game, three-city losing streak and avoided their first 10-game skid since 2011.

“To get those runs, yeah,” Pirates manager Clint Hurdle said. “A sigh of relief.”

In the long term, though, what mattered most as the Pirates began their final homestand might have been the performance of top prospect Mitch Keller. The rookie right-hander allowed only one run, struck out seven and thwarted Chicago’s scoring opportunities in his 11th and final start of the season.

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“You remember this one a little bit more,” Keller said. “In the offseason, this is the one you’re going to look back at, so I wanted to go out with a good one.”

Big innings have been a problem for Keller this season, and he was one pitch away from creating another. After recording two quick outs in the first inning, Keller gave up a single and a double, then walked Willson Contreras to load the bases. But he got ahead of Ian Happ and put him away with a high, 96 mph fastball to strand the runners.

“Just a confidence-booster,” Keller said. “When you get out of them, you look back at them the next time you’re in that situation, like what worked, what to go to.”

Keller gave up one run in the fourth, when Happ singled and scored on a Nico Hoerner double that a diving Bryan Reynolds couldn’t quite reach. Six pitches later, he was out of the inning with no further damage.

His performance ended a nine-game stretch during which the Pirates allowed nearly 10 runs per game and set them up to capitalize on the Cubs’ five errors. Held down by Hendricks all night, the Bucs sent 13 men to the plate and saw 48 pitches as they broke through in the seventh and pushed the Cubs to the brink of elimination.

It was not a flawless start for Keller by any means, as he needed 92 pitches to record 15 outs. But it was a good reminder of the 23-year-old rookie’s ability, a high note heading into the offseason, and a thumbnail sketch of what’s gone right and wrong since his Major League debut on May 27.

“Just a huge, huge, huge learning experience,” Keller said. “Everything about it was a learning experience, from the good outings to the bad ones to being sent down to being brought back up and everything in between.”

If your glass is half-empty, you’ll note that Keller allowed seven hits on Tuesday, bringing his season-long total to 72 -- or 13.5 per nine innings. He’s been susceptible to multiple-run innings, none more memorable than the six-run frame that began his big league career back on Memorial Day. And he’ll head home for the offseason with a 7.13 ERA.

“There’s a growth challenge that can come at this level. No. 1, it’s the best lineups he’s ever faced -- there’s no safety nets,” Hurdle said. “Then the importance of two-strike pitching, because there’s times down there [in the Minors] you just put people away, you just out-stuff them. Up here, it’s not as easy to out-stuff people. And there’s guys that make a living on two-strike mistakes.”

But there’s more to feel good about heading into 2020. Take a look at the fifth inning, for instance. The Cubs put two runners in scoring position with one out and Contreras due up. Keller fell behind with a first-pitch curveball then spun three straight sliders down and away from Contreras to strike him out.

One of many reasons that sequence was notable? Keller didn’t even throw that pitch earlier this year. Looking for a different weapon coming out of Spring Training, Keller picked up a slider/cutter like the one that worked wonders for Jameson Taillon last year.

“That’s probably one of my biggest ups from the year,” said Keller, who used his entire arsenal against the Cubs. “I started this year with three pitches and ended this year with four pitches that I feel really comfortable with.”

Keller induced 17 swinging strikes on Tuesday. The strikeouts came early and often, as they have all season.

He will end his first partial season in the Majors with 65 strikeouts and only 16 walks in 48 innings, the best strikeout-to-walk ratio among the Bucs’ active pitchers. He allowed six homers on the year, giving him an above-average rate of 1.1 homers allowed per nine innings.

Those numbers, along with his 3.20 FIP, indicate that better days are ahead for Keller, that he’s not far away from fulfilling his potential. The Pirates will need him to do exactly that next season, when they’ll be without Taillon while trying to rebuild a rotation that faltered too often this season.

“There’s been a really good learning curve for him -- an opportunity for learning, growth and experience,” Hurdle said. “I think he’s gotten more confidence without getting anything close to being comfortable. I think that’s a good place to be for a young player, that he’s built confidence and he knows it’s not going to get easier, but he’s starting to figure it out.”