PHILADELPHIA -- Roansy Contreras does not fear the fire.

Since returning from Triple-A Indianapolis, Pittsburgh’s tantalizing rookie has been tasked with navigating three of baseball’s tougher lineups. The Red Sox. The Braves. The Phillies. Multiple All-Stars. Multiple Silver Sluggers. It's a trio of teams that give veterans fits, but for a third straight time, the rookie battled and the rookie shoved.

The 22-year-old played the role of stopper in the Pirates’ 5-0 win over the Phillies on Sunday at Citizens Bank Park, throwing five innings of shutout ball with seven strikeouts as Pittsburgh snapped a seven-game losing streak. For manager Derek Shelton, these last three outings are unmistakable signs of Contreras’ evolution.

“We’re talking about three really good lineups, two of the better lineups in the National League, and Boston’s extremely tough,” said Shelton. “The fact that he’s been able to come out, execute and kind of stay within his plan -- like in the fourth [when he gave up a pair of singles and walked the bases loaded], he didn’t really get outside of his plan. He just continued to execute pitches. That’s a definite, really positive sign of Ro just taking steps forward.”

As has been the case since returning from Indianapolis, Contreras kept Philadelphia’s hitters off balance with a disgusting slider. He matched his career high of 17 called strikes and whiffs with his slider, tying the mark he set against the Red Sox on Aug. 17. In his last three starts, Contreras has generated 46 called strikes and whiffs on 107 sliders, good for a called strike and whiff rate of 43 percent.

While Contreras possessed crisp command of his slider from the jump, he needed a couple of innings to find his fastball. In the first three innings, Contreras totaled just five called strikes and whiffs on 27 fastballs. He lacked command with his heater and had several uncompetitive misses. In the fourth and fifth, Contreras found the feel; over those two frames, he induced seven called strikes and whiffs on the pitch.

“Contreras made some pitches,” said Kyle Schwarber. “He was a little erratic early on and was able to kind of settle in and find command of his fastball and use his slider down. He did a good job today. Tip your cap and [you’ve] got to be able to move on.”

Trouble arrived in the fourth inning. Bryce Harper, whom Contreras struck out in their first battle, singled on an 0-2 slider. J.T. Realmuto, whom Contreras also struck out, followed up with a single on a 1-2 count. Contreras maintained his composure.

The rookie struck out Jean Segura on three pitches, all fastballs, then retired Bryson Scott on a very soft lineout, but he walked Matt Vierling on four pitches to load the bases.

Edmundo Sosa smashed a 104 mph line drive on a slider that caught too much zone, but the ball nestled into Bryan Reynolds’ awaiting glove for the inning’s final out. Contreras expressed his relief by raising both hands in the air before returning to the dugout.

That fourth inning proved to be Philadelphia’s best chance of scoring off the right-hander. With the help of a diving stop by Rodolfo Castro to take a hit away from Nick Castellanos, Contreras retired the side in order in the fifth inning, ending his afternoon strong.

“He’s got a good arm,” said Phillies interim manager Rob Thomson. “We didn’t get much going. Sosa hits that line shot with the bases loaded right at the center fielder, and that was about the only time we had something going. He pitched good; you’ve got to give him credit.”

Contreras wasn’t the only young Bucco who shined on Sunday. The Pirates featured five rookie position players in the starting lineup to complement their rookie starter -- Oneil Cruz, Rodolfo Castro, Tucupita Marcano, Bligh Madris and Jason Delay -- all of whom chipped in at least one hit.

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Cruz tripled to lead off the game, then scored on Ke’Bryan Hayes’ opposite-field single. Marcano pulled a triple down the right-field line in the fourth inning, then dashed home on Greg Allen’s squeeze play. If two three-baggers weren’t enough, Reynolds got in on the action with a triple to begin the sixth, then scored on Michael Chavis’ single. Madris didn’t crack the triples club, but he banged a double off the very top of the right-field wall in the sixth, driving in a run and knocking Noah Syndergaard out of the game.

In addition to hitting his rally-starting triple, Marcano dazzled defensively all game long.

In the bottom of the first, Marcano made a sliding backhanded stop on Schwarber’s grounder, then fired to first for the assist. In the seventh, he cradled Sosa’s high chopper, stepped on second base for one, then threw to first for two. For the cherry on top, Marcano made a diving stop on Harper’s sharp grounder in the top of the ninth, popped up and fired to first for the out.

“Outstanding,” Shelton said. “Leaving his feet going both ways multiple times. He had a really good day defensively.”