PHOENIX -- If this is how Zac Gallen pitches when he’s not feeling great, then the rest of baseball is in a lot of trouble.

Gallen ran his scoreless streak to 28 inning as he shut the Royals down for 6 1/3 innings Wednesday afternoon in the D-backs' 2-0 victory at Chase Field.

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Gallen, who had a streak of 44 1/3 scoreless innings last year -- a club record and the longest in the Majors since 2015 -- entered the game having thrown 21 2/3 straight. Then he dominated the Royals, striking out 12 and allowing only four hits -- all singles.

“Would you believe me if I said I didn't feel great, or as good as I guess I felt the last start?” Gallen said.

The Royals certainly would have a hard time buying that.

“He does what a lot of people try to do, and he does it really well,” Royals first baseman Vinnie Pasquantino said. “He uses the same pitches, both sides -- and by same pitches, I mean, he’ll use a cutter, he’ll go to a changeup off that, he’ll go to a four-seam off that, and then he’ll use the big curveball off that.

“You watch it on video and see that’s what he does, but he’s playing chess. And he’s really good at it. He’s setting you up for not just the next pitch but for the following pitch after that. He’s moving your eyes around, and he did a really nice job today.”

For Gallen, pitching is like a game of chess, one he is constantly studying for with meticulous preparation.

So when he starts playing catch in the outfield and the ball doesn’t feel quite right coming out of his hand and it continues into his pregame bullpen session, he begins to try to find ways to make the most of what he has.

"I just felt the fastball wasn't as explosive as it was [my last start],” Gallen said. “Just feel like it just kind of didn't have that extra kind of life at the end there. Curveball felt OK. Change, it was about the only thing that really felt solid from start to finish. Curveball kind of was here or there.

“The fastball, just trying to pick my spots -- where to use it and not rely on it too heavily. Just use some other pitches to kind of get me through those innings."

The Royals picked up a pair of one-out singles in the first inning to put runners at first and third, but Gallen struck out Edward Olivares and Michael Massey to end the inning.

They did not get a batter to second base against Gallen the rest of his stint.

“In my last at-bat, he threw me one of the strangest pitches I’ve ever seen,” Pasquantino said. “He threw a cut-change. I’m not 100% sure if he meant to do it.

“He had lower-than-normal changeup spin with cutter movement. It was the pitch that the umpire got hit in the face, because the catcher was confused, too. That’s an anomaly pitch, but he’s able to do stuff like that and be around the zone. There’s a reason he’s got such a long scoreless streak going on.”

Gallen has recorded four straight scoreless starts of six-plus innings for the second time in his career. Since 1901, only three other AL or NL pitchers have multiple streaks of at least four straight scoreless starts of six or more innings -- Walter Johnson, Luis Tiant and Clayton Kershaw.

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Should Gallen manage to run his scoreless streak to 30 innings, he would join another impressive club. Six pitchers over the past 40 seasons have had two separate single-season scoreless streaks that have last 30 or more innings: Kershaw, Cliff Lee, Brandon Webb, Kenny Rogers, Roger Clemens and Orel Hershiser.

Hershiser, of course, owns the Major League record for consecutive scoreless innings, 59 in 1988.

Gallen got questions about his streak Wednesday. Unlike last year, when it was a new experience for him, he is better equipped to deal with the pressure a streak can bring. When he faced the Royals last year in the midst of his streak, he admitted that it was the one time he let it get to him and was pitching “defensively.”

“Now it's like, ‘OK, if it's going happen it's going to happen,’” Gallen said. “You can go out there and make really good pitches and get unlucky, or you can make bad pitches and get lucky. So I think I just mentally understand that you’ve got to be on the offense out there.”