PHOENIX -- It started innocently enough with an infield single. The next two Tigers hitters singled on balls that had a .180 and .140 expected batting average, per Statcast.

That loaded the bases for Javier Báez, whose strengths and weaknesses are well known.

"We all know the scouting report on him," manager Torey Lovullo remarked. "He's an extremely dangerous hitter, a free swinger and he can catch mistakes."

D-backs veteran right-hander Merrill Kelly was well aware of that. He threw a fastball in for a ball to start the at-bat. Then another fastball inside that Báez fouled off. Kelly then went off the plate down and away with a curveball that Báez flailed at.

The plan was then to either go away with another breaking ball or bounce one to try to get Báez to chase.

Kelly, though, missed his spot. Báez, on the other hand, didn't. With a prodigious swing, Báez sent a curveball into the bleachers in left-center field for a grand slam as the Tigers beat the D-backs, 5-1, at Chase Field on Friday night.

"I just think that was a ball that was a mistake," Lovullo said. "With that count and in that situation, you don't want to throw that quality of a pitch to any hitter, let alone someone who can do the damage that he's able to do."

Kelly knew it, and it was the one pitch out of the 99 he threw that he really wanted to have back.

"I just missed with it," Kelly explained. "It was supposed to be out of the zone. He chased the one before that pretty bad. So I would imagine in his mind he was going to try not to get beat like that again. It wasn't a bad pitch. It was at the bottom of the zone, but [with] two strikes to him it's got to be a chase pitch and I just left it up and he didn't miss it."

Báez was indeed looking for Kelly to try to make him chase again.

"I mean, the way they were pitching me today was really off the plate," Báez said. "And I was looking for balls off the plate, the way I hit. And that breaking ball that I missed, [was] way away. I knew he was going to throw it away again. I was waiting for it, but it was kind of a middle-middle pitch."

One of Kelly's strengths as a pitcher is his ability to turn the page quickly after a bad pitch or inning. It doesn't rattle him, and he doesn't let it impact the rest of his outing.

Friday's start was a prime example. One bad pitch equaled four quick runs, but rather than get frustrated and allow things to spiral, he reset. Kelly retired the next three hitters and kept the Tigers off the board until departing after the sixth.

"I think tonight that's kind of what I'm going to take away from the game," Kelly said. "It's like I just got beat on one pitch. Obviously giving up a grand slam sucks. I would have liked to not have done that. But I feel like at the end of the day, I can walk away knowing that I just missed with one pitch. The rest of the game was fine. Made pitches, got outs. They strung together seven hits, but in my mind not a ton of them were hit very hard, so I can kind of live with that. I'm just obviously mad that the one pitch that [I] didn't execute came back to bite me."