BALTIMORE -- Angel Zerpa was tasked with getting the Royals out of the fifth inning in his postseason debut. But it was not going to be easy.

The challenge: Bases loaded with one out and Colton Cowser in the batter’s box. Due up after Cowser was All-Star catcher Adley Rutschman. The Orioles had tied the game at 1 with a Cedric Mullins homer to lead off the inning. Thousands of O’s fans loudly cheered in the stands.

Zerpa stayed focused and helped the Royals to a 2-1 win to sweep the Wild Card Series against Baltimore on Tuesday, clinching a spot in the American League Division Series against the Yankees.

“The plan was to not miss pitches. Dominate and punch them out and execute good pitches when we’re on the rubber,” Zerpa said in Spanish about his approach to facing Cowser and Rutschman.

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First up was Cowser, who led MLB rookies (along with Padres All-Star Jackson Merrill) with 24 home runs during the regular season. Zerpa worked a 1-2 count against Cowser. The left fielder swung at the sinker, but the ball made contact on the knuckles of his left hand, which resulted in a fracture.

Despite being hit by the pitch, Cowser still struck out because he attempted to hit a third strike and the ball touched him according to MLB rule 5.09 (a)(6). The rule also states that when the batter is touched by a pitched ball which does not entitle him to first base, the ball is dead and no runner may advance.

Two outs. Bases still loaded.

Rutschman was up. Zerpa’s approach remained the same. The 24-year-old hurler had fallen behind in the count but worked his way back with a strike and a foul ball. On the fifth pitch of the at-bat, the O’s catcher made contact with a slider, but Bobby Witt Jr. stopped the ball in the shallow outfield grass and threw to first baseman Yuli Gurriel for the inning-ending out.

Zerpa had already begun to make his way off the mound, and he clapped as he watched the play unfold. He had prevented the Orioles from taking a lead that could have forced a Game 3 in the American League Wild Card Series.

Zerpa returned to start the sixth and got Austin Slater to chase for his second strikeout of the night, completing one full clean inning.

The plan all along was to use Zerpa in high-leverage situations during the series, according to manager Matt Quatraro.

“Clearly we didn't want it to be like that [exact situation],” Quatraro said. “But he throws a ton of strikes. He's got a 98 mile-an-hour sinker, and his breaking ball is so much improved since he was sent down to Triple-A a couple months ago.”

Zerpa was optioned to Triple-A on Aug. 26 to work on the pitch. He said he maintained the same mentality that he has always had and did not let being optioned bring him down.

“I understood [the decision] because there are really good batters in the big leagues and you need to have a secret weapon for everything,” he said.

The new and improved pitches were on display on Wednesday.

His sliders averaged 39 inches of drop in the regular season, and Zerpa upped that to 46 inches of drop on Wednesday night. His slider also had more horizontal break -- nine inches compared to five inches during the regular season.

Cowser struck out on the sinker, Rutschman grounded out on the slider and Slater chased another slider.

“So credit to [Zerpa], credit to the player development,” Quatraro said. “Dane Johnson is the pitching coach in Triple-A that just nailed it with helping him get that breaking ball back, and Dave Lundquist. It's really remarkable what [Zerpa’s] doing. He loves to pitch. He's one of those guys that competes like nobody's business. It's so much fun to be around him.”

Even before Zerpa’s heroics had concluded, Bobby Witt Jr. knocked in his second go-ahead RBI of the series in the top of the sixth, and the rest of the bullpen stepped up to hold the Orioles at one run and maintain the lead.

The Royals’ bullpen now owns a 1.73 ERA (17 earned runs in 88 1/3 innings) in 24 games since Sept. 4, which ranks second in MLB during that span behind the Guardians’ bullpen with a 1.33 ERA.

“These guys, it's so impressive that they believe in themselves and they trust their trust and they just come after some of the best hitters in the world,” Quatraro said. “... You come here against that team and give up one run in 18 innings, sign me up.”