Zac Gallen walked off the Dodger Stadium mound with a runner on first and no outs in the eighth inning on Wednesday night. It was another impressive outing for the D-backs right-hander, who had allowed just one hit and had made the one measly run his offense had scored hold up to that point.

Yet Gallen seemed unhappy with himself as he paced in the dugout.

While everyone wearing a D-backs uniform would be unhappy a few innings later when the Dodgers rallied to tie the game in the ninth and again to win it in the 10th by a 3-2 margin, the reason Gallen was upset earlier is also what makes him so good: He’s never satisfied.

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“I'm kind of a perfectionist,” he said. “Not very maniacal about it, but I always want to go out there and get everybody out. Just kind of stinks leaving runners on base. Wish I could have finished that up and put them away.”

This spring, catcher Carson Kelly said he thought Gallen was going to wind up being a great pitcher. Why did he feel that way? Because he saw, coming up in the Cardinals’ system with Gallen, how success only made him want to work harder.

There was always something he could improve on. Pitch sequencing, preparation, tunneling his pitches -- it was just a never-ending quest for Gallen.

“That’s that drive that he has,” Kelly said.

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Gallen has made 23 starts as a big leaguer, and he has yet to give up more than three earned runs in any of those starts, which is a Major League record.

"You've got to give credit to Gallen, who pitched a heck of a ballgame,” Dodgers manager Dave Roberts said. “Only made a handful of mistakes the whole night. It was fun to watch him compete and make pitches, even though against us. To see the pitching back and forth was a lot of fun."

The back and forth that Roberts referred to was the fact that he had his own ace right-hander on the mound in Walker Buehler.

Buehler pitched well -- five shutout innings of two-hit ball in a return from the injured list. With Buehler 26 years old and Gallen 25, this could be the first of many classic matchups between these two in the National League West.

"The guy's had a pretty incredible start to his career,” Buehler said. “I imagine we'll square off a few more times. Fun guy to watch; he mixes and matches."

As it turns out, Gallen has kept his eye on Buehler as well. In the first inning, Gallen turned to pitching coach Matt Herges and remarked about how awesome of a pitcher Buehler was.

“Every time we play him, I try and just sneak a peek of him playing catch,” Gallen said. “I just think it's unbelievable the way his body moves in space. And then the pure stuff. He's somebody that I've seen since I think ‘15 or ‘14, maybe, back in the Cape [Cod League], but he's just gotten unbelievably better over those years, and I tip my hat to him -- he’s pretty good.

“I don't know him at all. I think we have some mutual friends, you know how baseball is. I haven't talked to him. Maybe one of these days, I'll go over and say ‘what's up’ and maybe talk shop with him.”

Gallen became the first D-backs pitcher ever to throw at least seven innings and allow no more than one hit at Dodger Stadium.

The hit Gallen allowed came on his first pitch of the night, which was knocked into center by Mookie Betts.

“He just mixes his pitches and keeps it from getting out over the middle of the plate,” Betts said. “Got to give credit where credit's due."

Even if Gallen is reluctant to accept it.