With the score tied at 4, Willie Bloomquist and Justin Upton led off the eighth with back-to-back singles. Montero followed by hitting a ball to the left-center field gap off Royals reliever Tim Collins. Center fielder Mitch Maier dove and nearly made the catch, but the ball just nicked the top of his glove and went to the wall. Both runners scored to give the D-backs a two-run lead.
The go-ahead hit was the second of the night for Montero, who also gave the D-backs an early 1-0 lead with a double in the first inning off Royals starter Luis Mendoza.
Perhaps it was no coincidence that the Arizona offense got on track the day outfielder Chris Young returned from the disabled list. Young only went 1-for-4 in his return, but he contributed a two-run double down the left-field line in the top of the sixth inning that briefly gave the D-backs a 4-3 lead.
Young's hit wasn't the biggest, but after the game he was praised for bringing some more offensive firepower to the lineup.
"I think it's a way different lineup with him in it," said D-backs starter Joe Saunders, who allowed three runs in six inning in a no-decision. "It gives us more balance, gives us more power, gives us more opportunities to do things. I feel like we're definitely better with him."
Young said he was just glad to be back, regardless of what his line looked like after the game.
"It was great," Young said. "No matter how many at-bats you get in the Minor Leagues, when you get here it's just completely different. You've got a little more adrenaline flowing. You're locked in a little more. ... It was great to be back in the lineup. It didn't even matter about the results today. Just to get back in the groove of things and get my legs back under me, and get into a baseball game, it was great."
Young's go-ahead double capped a sixth inning that really turned the tide. Mendoza had been nearly untouchable throughout the first five innings, surrendering just one hit during that span. But the D-backs finally got to him in the sixth.
Down 3-1, Gerardo Parra, Bloomquist and Upton collected back-to-back-to-back singles to open the inning, with Upton's scoring a run. After Mendoza struck out Montero, Young doubled.
"[Mendoza] had a tremendous sinker, He did a really nice job of keeping hitters off-balance with it," Royals manager Ned Yost said. "He got through five and had only given up one hit, but just kind of got where he made a couple of pitches that got elevated a little bit. And, before you know it -- boom!"
The lead was short-lived, though, as Royals outfielder Alex Gordon tied the game with an RBI single in the bottom of the seventh off Arizona reliever Brad Ziegler.
Saunders wasn't quite the unhittable force his counterpart was through the first half of the game. The lefty had runners at the corners in both the first and second innings. Saunders escaped the first without any damage, but he wasn't as fortunate in the second.
With runners at the corners and one out, Humberto Quintero deposited a double down the left-field line, bringing in both runners and giving the Royals a 2-1 lead.
The trouble continued for Saunders in the third, as the third pitch he threw to Royals first baseman Billy Butler was crushed to straight-away center field for a home run, bumping the Royals' lead to 3-1. The 414-foot blast was Butler's seventh long ball of the season.
Saunders managed to settle down, though, allowing zero runs after Butler's homer. The lefty went six innings, giving up three runs on eight hits and two walks.
"The first three innings were pretty dicey," Saunders said. "I don't know how many pitches I had. It felt like I had 100, felt like I was out there for a long time. I just told myself after three to keep making good pitches and start working ahead of guys, letting your defense play for you. They hurt me. They're a quality lineup. They made me pay for being behind in the count. I just had to settle down and eat up some outs."
Ziegler picked up the win, his third of the season, and J.J. Putz tossed a scoreless ninth for his eighth save.
The win makes it back-to-back victories for the D-backs for the first time since May 1. The team has struggled of late, but Young thinks things are turning around.
"We have a great offense," Young said. "With the majority of teams in baseball, you're going to have some rough patches that you run across. The faster you can find a way to get out of that, the better. It looks like the guys have started coming around and swing the bats."