After Jason Kubel had homered off Francisco Rodriguez on the first pitch of the eighth to tie it at 1, Milwaukee's ninth-inning rally started with a leadoff walk to Aramis Ramirez by Arizona rookie Patrick Corbin, who was on in relief.
The Brewers sent the speedster Gomez in to pinch-run, and the D-backs knew he was going to attempt a steal. Arizona prides itself on shutting down the running game and Corbin threw over to first eight times with the next batter, Corey Hart, at the plate.
Corbin got Hart to fly out and threw over to first one more time before his first pitch to Rickie Weeks.
"I don't know, it might be," Gomez said when asked if the nine pickoff attempts were a record. "I thought he was going to throw three, four more times. I started getting ticked off. I'm telling you man, honest, I don't like it when they throw that many times over there. Throw it to the plate, I got to go."
Corbin delivered a 93 mph fastball to the plate and Gomez took off. The pitch was a little low and outside and Montero thought his only chance to get Gomez was to throw from his knees.
The ball skipped past second baseman Aaron Hill and into center field.
"I knew he was going to try to go," Montero said. "He had a good jump. I feel like I got rid of the ball quick. The ball took a bad hop to Hilly and unfortunately he was unable to handle it. But it was a bad throw, anyway."
Gomez quickly got to his feet and dashed for third.
Meanwhile, a charging Parra picked up the loose ball and threw to third to try to get Gomez.
"I thought I could have made it a close play," Parra said.
The one-hop throw deflected off a sliding Gomez and wound up in the seats behind the third-base dugout as Gomez easily trotted home for the game-winner.
"It was a perfect throw," third baseman Willie Bloomquist said. "It's not [Parra's] fault. I don't think he would have been out, but he made a perfect throw."
This was not the first time the D-backs watched Gomez celebrating with his teammates at home plate. Gomez stole second and scored on a single in the bottom of the 10th inning of Game 5 of the National League Division Series.
The stakes, obviously, were less Sunday, but frustrating for the D-backs nonetheless as they dropped the series to the Brewers and finished their road trip at 2-4.
With Josh Collmenter and Yovani Gallardo hooking up, the game was as expected a pitchers' duel.
Collmenter tossed 14 scoreless innings against the Brewers last season and allowed one run in seven innings against them in the NL Division Series.
"I felt really good," Collmenter said. "I was able to put the pitches where I wanted to and made pitches when I needed to, and aside from a couple of pitches out over the plate that got hit, I was able to move the ball in and out and keep it down, for the most part."
Milwaukee's lone run against Collmenter, who lasted six innings, came in the fourth when Norichka Aoki led off with a double to right, moved to third on a wild pitch and scored on a groundout by Nyjer Morgan.
Gallardo came into the game 6-0 with a 1.21 ERA in six starts against the D-backs, and Arizona once again had trouble figuring out the right-hander.
The D-backs battled in an attempt to run up his pitch count and with two outs in the seventh, the approach began to pay off.
Pinch-hitter Chris Young drew a two-out walk and he advanced to third when Rickie Weeks committed a pair of errors on Bloomquist's grounder. Stephen Drew then coaxed a walk to fill the bases and that ended Gallardo's day.
"Great job by 'Yo' -- outstanding ballgame," Brewers manager Ron Roenicke said. "Great location in the fastball, great curveball, slider."
Reliever Jose Veras fell behind Justin Upton, but was able to strike out the slugger to end the threat.