PITTSBURGH -- Remember when a short start all but guaranteed trouble for a problematic Pirates bullpen? Well, those days might be over.

A two-hour, five-minute rain delay ended right-hander Joe Musgrove’s promising outing after only three innings on Tuesday night at PNC Park. With a lead in hand, Pittsburgh manager Clint Hurdle only needed to figure out a way to navigate the final six innings. The Bucs’ bullpen answered the call, recording 18 outs in a dominant performance that sealed the Pirates’ 5-1 win over the Cubs.

• Box score

“We’re all feeding off each other, and we’re all putting each other in good spots,” said right-hander Clay Holmes, who struck out four over two perfect innings. “When the guy in front of you does his job, it helps you. We’re building off each other and putting each other in the best situations that we can when we come in.”

As a result, the Pirates’ bullpen is in a much better situation than one might have thought possible a month ago. So is Pittsburgh, now only four games behind the division-leading Brewers and three games out of a National League Wild Card spot.

“I think we’re in a really good place. This is kind of where we were at last year heading into the All-Star break,” Musgrove said. “We caught some fire right before the break and were able to carry it into the start of the second half. We don’t try to focus on what other teams are doing. When you’re playing in-division teams, it’s nice to be able to grab wins. It’s an immediate jump in the standings, not having to rely on other people to win or lose, but I think we’re just focused on what we’re doing in here.”

On June 10, Pittsburgh’s ’pen owned a 5.63 ERA, the third-worst mark in the Majors. They were coming off a particularly rough stretch from May 21-June 10, when their relievers allowed 76 earned runs in 94 1/3 innings. Since then? The relief corps has a Major League-best 2.16 ERA over 19 games.

“They’ve just continued to work,” Hurdle said. “The job that they do showing up every day and preparing, learning along the way, spending time with [coach Heberto] Andrade or [bullpen coach Euclides] Rojas, tightening things up, all the prep work and flat-ground work and bullpen work, all of them are getting sharp. Tonight, that was pretty special.”

So, too, was the performance of Adam Frazier. Back in the leadoff spot after his five-hit, four-double performance on Monday, Frazier did the heavy lifting for Pittsburgh’s lineup by going 4-for-4 with three runs, a double in the third and a three-run homer in the fourth.

“He’s done a really spectacular job the last two days,” Hurdle said.

The bullpen’s turnaround has been a gradual group effort, and it was on display as the Pirates won for the ninth time in their last 12 games. It might not have been necessary on Tuesday, however, if not for the rain that knocked out Musgrove after he struck out four over three efficient innings.

It was another frustrating finish for Musgrove, who was previously ejected from his June 10 start in Atlanta after 18 pitches. On the bright side, he’ll be even more energized when he starts Sunday’s first-half finale against the Brewers.

“It’s a bummer to leave the bullpen with that much work, but personally I felt really good,” Musgrove said. “I felt like my stuff was sharp. I had a lot of weapons still to use that I hadn’t shown them yet, so I feel like we were setting up to go deep in the game. But the bullpen did an awesome job.”

Francisco Liriano, quietly thriving and providing key leadership in the bullpen, scaled the mound after the lengthy rain delay and needed only 11 pitches to finish the fourth. Richard Rodriguez, unscored upon in 14 appearances since May 30, took care of the fifth.

Then came Holmes, still settling into his role during his first full season as a reliever. The 26-year-old right-hander put together perhaps his most dominant performance at this level by pairing better control with his power stuff, including a fastball that topped out at 98.3 mph on Tuesday.

The Cubs swung and missed on six of Holmes’ 24 pitches, took six of them for strikes and only put two in play -- one for a bunt groundout and another for a routine groundout to third base.

“Getting comfortable each time out, just trusting my stuff when I get out there,” Holmes said. “Each time out, I’m getting more and more comfortable. I’m able to throw offspeed for strikes. It takes pressure off the sinker, just getting ahead and trusting my stuff.”

Setup man Kyle Crick handled the eighth, striking out David Bote to strand a pair of runners in scoring position. The only pitcher who allowed a run on the night was closer Felipe Vazquez, in the middle of another All-Star-worthy season, as he surrendered a two-out RBI double to Willson Contreras in a 29-pitch ninth.

It was an unfitting end to an otherwise excellent night for the Pirates’ bullpen.

“Full confidence in them,” Frazier said. “Hit a little rough patch, which everybody’s going to do at times. It just happened to be more than one guy hitting that patch at the same time, so it was tough. They’ve righted the ship, and hopefully they can keep that rolling.”