PHOENIX -- Like most big league pitchers, Zac Gallen doesn’t put a lot of stock into how his pregame bullpen session goes. There have been days he’s felt great in the bullpen and struggled in the game, and games where he left the bullpen thinking it could be a long night, only to dominate.

Tuesday night against the Yankees was one of those nights where he was especially sharp in the bullpen -- but in Gallen’s mind, the true measure of how well a pitcher throws isn’t about warmups or any of the new-school metrics like induced vertical break.

The separator is whether a pitcher quickly makes adjustments once the game starts.

That’s exactly what Gallen was able to do against the Yankees, overcoming a pair of walks in the first inning to hold the Bronx Bombers scoreless through six innings in Arizona’s 7-0 win in front of a raucous crowd of 39,863 at Chase Field.

It was the first time the D-backs have shut out the Yankees since beating them, 4-0, in Game 2 of the 2001 World Series.

"This was all about Zac Gallen tonight,” D-backs manager Torey Lovullo said.

Gallen allowed just three hits and struck out six on Tuesday in handing New York its first loss of the season following five wins. Across two career starts against the Yankees, he has yet to give up a run in 12 innings.

Gallen issued a walk to Gleyber Torres to open the game and coaxed a double play from the red-hot Juan Soto before issuing another walk, this one to Aaron Judge.

“My warmup was really good, and then in the first I walked two guys,” Gallen said. “I just tried to make the adjustment.”

The adjustment involved his direction towards the plate. A small change, so subtle it might not be visible unless you know what you’re looking for, but it paid off.

“Everything kind of started to click a little bit after that,” Gallen said.

Said Yankees first baseman Anthony Rizzo of Gallen, “He was just hitting spots. Especially with two strikes, he wasn’t really missing over the plate at all.”

The D-backs gave Gallen some early run support when they jumped on Nestor Cortes for three runs in the first inning, thanks to RBI singles by Blaze Alexander, Eugenio Suárez and Gabriel Moreno.

Cortes settled in after that, but the D-backs tacked on some insurance in the seventh with Christian Walker's three-run home run. They also added a run in the eighth, when Geraldo Perdomo scored on a wild pitch.

Gallen finished third in the NL Cy Young award voting a year ago, and when he takes the mound, the knowledge that he’s likely to pitch very well is actually a help for the Arizona offense.

“It's a funny dynamic,” Walker said. “It kind of takes pressure off of us as an offense where it's like, 'Hey, just you know, let's just get a couple [runs]. That could be good enough today.' That headspace tends to lead to more runs and better at-bats and giving yourself a little more grace and freedom in the box, because you trust the other side of the ball so much and that little edge can free up an offense big time.”

The offense struggled to get anything going against the Yankees in the D-backs' series-opening loss, but on Tuesday they put together good at-bats up and down the lineup.

“I love the scenario the last two days,” Walker said. “Where yesterday we had a hard time getting things going. We showed up today almost like we paid it no mind, snapped back into who we were, trusted ourselves, didn't try to do too much. To bounce back like this and put some runs up against a good team was important for us as an offense.”