PHOENIX -- Over the past few days, most of the talk around the National League Championship Series has been centered on the Phillies’ potent offense. 

Led by a star-studded trio atop their lineup, the Phillies are hitting homers at an historic pace this postseason. The D-backs watched as six balls left Citizens Bank Park through the first two games of the series.

For the D-backs to flip the momentum in the NLCS, they knew they needed to pitch better. They had to find a way to contain a lineup that arrived at Chase Field with a ton of confidence after scoring 15 runs to start the series. 

Brandon Pfaadt gave the D-backs exactly what they needed, and so much more.

The rookie right-hander delivered the pitching performance of his career, tossing 5 2/3 scoreless innings and striking out nine in the D-backs’ 2-1 walk-off win over the Phillies in Game 3 of the NLCS on Thursday afternoon at Chase Field.

“Brandon was unbelievable,” said D-backs manager Torey Lovullo. “Brandon threw the baseball as good as you possibly could have hoped or imagined. Once again, it’s a young kid stepping into a huge environment and executing at a very high level. That’s what stands out more than anything.”

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It didn’t take long on Thursday for the sold-out crowd at Chase Field to notice Pfaadt was ready to deliver a strong performance. Pfaadt struck out leadoff hitter Kyle Schwarber, who has three homers in the series, with a perfectly located sweeper down in the zone to catch him looking.

After Trea Turner reached on a broken-bat single in the first, Pfaadt quickly erased that, getting Bryce Harper to ground into a 4-6-3 double play. In the third, Pfaadt gave up a one-out double to Brandon Marsh, but responded by striking out Johan Rojas and Schwarber to end that threat.

Pfaadt struck out six batters through three innings, joining Hall of Famer Randy Johnson as the only D-backs pitchers to record six punchouts in the first three frames of a postseason start. 

“Probably the best I’ve ever seen him throw,” said D-backs outfielder Corbin Carroll, who played with Pfaadt throughout the Minors. “He had both fastballs working. That’s quality pitch after quality pitch.” 

While Pfaadt’s dominance vs. the Phillies' order in the first few innings might’ve come as a surprise to some people, the right-hander had the advantage of not having faced the Phils in the regular season. None of the Phillies’ hitters had gotten a look at Pfaadt in the past, setting up a test for the young righty once the order turned over for the second time. 

But as he did all afternoon, Pfaadt stepped up to the challenge. He retired the last 10 batters he faced, striking out five of them. Pfaadt’s nine strikeouts with no walks are the most punchouts by a rookie in a postseason start without a walk since Don Newcombe struck out 11 in Game 1 of the 1949 World Series. Pfaadt also became the youngest starting pitcher in D-backs history to strike out nine or more in a postseason start.

“It feels great. It feels great to pick up the team,” Pfaadt said. “We went down 2-0. That was a big win for us. We knew that going in. I think coming out with that win, that helps us get some momentum on our side."

Pfaadt said getting the four-seam fastball up in the zone was the biggest key to his success. He recorded nine swings and misses with the pitch as part of 17 overall whiffs on the night, which was a career high. Pfaadt also attributed his success to being able to handle the moment better.

The rookie right-hander was thrust into starting Game 1 of the NL Wild Card Series against the Brewers. Arizona ended up winning that game. Pfaadt gave a scoreless start in Game 3 of the NL Division Series against the Dodgers to clinch the series. Then, there was Thursday’s Game 3 against the Phillies, and he was able to put the team on his back. 

“He did a nice job,” said Phillies manager Rob Thomson. “He threw strikes, mixed his pitches well, kept us off balance. It’s a guy we haven’t seen before, so it’s a little different. But I thought he did a good job.”

Coming into the postseason, it was easy to question whether the D-backs had enough starting pitching behind co-aces Zac Gallen and Merrill Kelly to make a deep run. Through three postseason starts, Pfaadt has put all of those concerns to rest.

So as Lovullo went to the mound to pull Pfaadt for left-hander Andrew Saalfrank with two outs in the sixth, the home crowd booed their manager. They wanted the right-hander to stay in the game. That’s the level of confidence Pfaadt has instilled in everyone around the organization this month.

But Pfaadt had easily done enough to help the D-backs line up a bullpen that has starred in October. It was a performance Pfaadt won’t forget, and it was everything Arizona could’ve hoped for.

“Pfaadty had his stuff today, man,” said D-backs outfielder Pavin Smith. “He really figured it out and had a career day today. … And to do it on the biggest stage is huge.”