ST. LOUIS -- For the first time on American soil, "The Final Boss" got an opportunity to pitch to his nickname on Saturday.

Seung Hwan Oh retired the Brewers in the ninth to close the Cardinals' 3-0 win and earn his first Major League save. He adds it to the 357 he collected over an 11-year career pitching professional in Japan and Korea, where Oh was fitted with the most apt of nicknames and established himself as arguably the greatest closer in league history.

"Happy is one word I would describe the feeling as," Oh said afterward, speaking through translator Eugene Koo. "I understand the importance, and that it's one of the major accomplishments I've achieved in my baseball career. I'm very happy I could contribute to the team."

Saturday's save situation was the Cardinals' first since manager Mike Matheny announced a changed role for Trevor Rosenthal. Matheny had not specifically name Oh the team's new closer, but the fit was natural given Oh's extensive late-game experience.

"He's continuing to impress us," Matheny said. "And I think the rest of the league is obviously seeing that this guy is for real."

The Cardinals signed Oh in January to help fortify the back end of their bullpen. He wasn't promised an opportunity to close at that time, though Oh insisted on Saturday that was never necessarily his dream.

"My goal was actually to be on the mound of Major League Baseball," he said. "I didn't see this coming. My mentality right now is not thinking of myself as a closer. I'm trying to fill in the empty space where Rosey used to be. I'm just trying to get guys out."

To the latter objective, Oh has done quite well. The rookie right-hander ranks second in the National League with 55 strikeouts, fifth with a 0.85 WHIP and sixth with an ERA of 1.54. He had registered 14 holds, too, by quickly becoming Matheny's go-to reliever in the highest-leverage spots leading to the ninth.

Now, until Oh relinquishes it or Rosenthal earns it back, the ninth belongs to him. So, too, does Saturday's baseball, which Oh tucked away after closing the game with a strikeout of Kirk Nieuwenhuis.

"He's got great stuff. His stuff plays anywhere," said starter Adam Wainwright. "He's got that deceptive delivery and good stuff to go with it. He is obviously not scared of any situation. They call him the Stone Buddha for a reason, right? He has that look on his face that he has been there and done that and been in bigger moments."