Ryan Mattheus had never been in a bigger spot in his life. Like many on the Nationals roster, this was his first taste of the postseason. And Nationals Manager Davey Johnson threw him far into the deep end, calling on the sinkerballing right-handed reliever in the seventh inning with the bases loaded and no outs in Game 1 of the National League Division Series.

Read that again and imagine: Your first playoff appearance is before a sold-out crowd of 47,078 white flag-waving fans at Busch Stadium facing the heart of the Cardinals lineup. But that’s the situation the fiery 28-year-old was thrust into in a 3-2 win on Sunday. And with two pitches, Mattheus notched the three biggest outs of his career and saved the inning.

“It’s very unusual,” said Mattheus, who threw more pitches in the bullpen than in the game. “Thinking back on it, there’s not much to think about, I only threw two pitches. I was in there and it was over before anything happens. That’s the best-case scenario.”

While Tyler Moore provided the go-ahead two-run single in the eighth inning and Jayson Werth snatched back a two-run home run in the sixth inning, none of those may have had as much of an impact were it not for Mattheus’s crucial inning.

“That was a huge momentum swing,” Ryan Zimmerman said. “It gave us kind of a shot in the arm to come in, to be down obviously and for them to not be able to tack on any runs there was huge.”

In his second inning of relief, Craig Stammen’s first batter, Jon Jay, reached on a throwing error by Zimmerman. Carlos Beltran singled to center field. Mattheus was told that if anyone reached that inning, he would start warming and he thought he would come in to face Cardinals slugger Matt Holliday. But Johnson left Stammen in to face him.

Mattheus said he wasn’t ready to come in to face Holliday. But once Stammen hit him with a pitch to load the bases with no outs, Johnson emerged from the dugout calling for Mattheus. He wasn’t trying to miss any bats with his pitches; he knew he needed groundouts.

“Randy Knorr’s told me something all year, and it’s get three outs before they touch home plate, and it doesn’t matter how you do that,” Mattheus said, referring to the Nationals’ bench coach. “If they hit three rockets at somebody or they hit three balls to the warning track, if you get three outs, you’ve done your job.”

Mattheus fired a sinker to Allen Craig, who hit .403 with runners in scoring position during the season. The pitch was over the middle of the plate, “nothing special.” Mattheus said. Craig rolled over it and hit it to shortstop Ian Desmond, who threw home to nab Jay for the first out. Mattheus’s next pitch to Yadier Molina was a sinker that “ran more than it sank but got in on his hands so he couldn’t do much with it.”

Molina rolled over it, too, and Zimmerman made a tough scoop to his left, threw to Danny Espinosa at second who made a quick turn to complete the double play. Mattheus pumped his right fist. He ran off the mound to the dugout, and pumped his first again and high-fived teammates.

“I was going crazy when I came back in the dugout,” he said. “… You can’t really prepare for these situations. And us being a younger squad, and me only being here in a short time in the big leagues, that was the biggest situation I’ve ever pitched in.”