SCOTTSDALE, Ariz. -- When the D-backs decided to slow play ace right-hander Zac Gallen this spring, they knew there was not a lot of room for error should the schedule not line up just so.

But after his penultimate start of the spring in a 2-0 win over the Angels on Sunday afternoon at Salt River Fields, Gallen is exactly where he wants to be with his expected Opening Day start 11 days away.

Gallen allowed just one hit and one walk while striking out four over 4 1/3 scoreless innings, and because he was so efficient with his pitches, he was able to unexpectedly get to touch the fifth inning.

Overall, Gallen threw 58 pitches (34 strikes). And with one more start this spring, he can get to the pitch-count range he would need to be at for Opening Day.

“Zac was unbelievably efficient today,” manager Torey Lovullo said. “We ran it back out there for his fifth inning, just to drive his pitch count up. Touching that inning was super important, getting stretched out is equally important with his pitch count.

“But I thought overall it was clearly one of the best spring outings that we've seen from any of our starting pitchers. It was very Zac-esque.”

For Gallen to be happy with a start comes down to how he feels. Is his timing with his delivery where it needs to be? Does the ball feel good coming out of his hand? Is the shape of his pitches where he wants them?

Against the Angels, he checked all those boxes.

“This probably is maybe the best I’ve felt in a while,” Gallen said. “Just gratifying because I've been working on stuff just even over the last year or so. I feel like everything really started to click today.”

Gallen will go back and look at the analytics from his start to see if the TrackMan data lines up with how he felt and how he thought things went, and then, he’ll go from there.

Gallen’s secondary offerings -- slider, changeup and curve -- were sharp, but the velocity on them was down an average of 3 mph on the slider and curve, and 1.5 mph on the changeup.

While he wasn’t intentionally making those pitches slower, Gallen pointed out that he is not throwing them with 100 percent effort at this point in the spring.

“Right now, we'll just start at maybe throwing them at 85 percent,” Gallen said. “And then as the season progresses be able to add that kind of little extra gear to it.”

Gallen finished third in the National League Cy Young Award voting last year, and the D-backs will once again count on him to front their rotation as they try and defend their NL pennant.

Considering he threw a career-high 210 innings during the regular season and another 33 2/3 in the postseason, the D-backs wanted to bring Gallen along a little slower this spring. That approach, so far, has paid dividends.

“I feel pretty solid,” Gallen said. “I felt solid pretty much the whole camp so far, honestly. You know, as I get more experience doing this, you understand the signs and the tells of when I’m getting close, whether the box score shows that or not. I’m feeling good and it’s all starting to narrow into a range, so I feel pretty solid.

“Obviously, there’s more work left to be done and it’s a long season. Nothing in Spring Training counts, but it’s good to have a solid foundation.”