LOS ANGELES -- It couldn’t have been easy for Torey Lovullo. The D-backs' manager had his best pitcher on the mound in perhaps the most important inning of his team’s season. Yet there was Lovullo, walking up the dugout steps and raising his left hand to call for an unproven rookie reliever at a raucous Dodger Stadium.

It wasn’t easy for Zac Gallen either. Arizona's ace had stifled one of the best offenses in baseball for five innings. He’d masterfully escaped a jam in the fifth, and he’d thrown only 84 pitches when Lovullo emerged with one out in the sixth -- fewer pitches than he’d thrown in any start since May.

But two hours later, as they both reflected on that fateful frame from the Dodger Stadium interview room, Gallen and Lovullo were doing so with a two-games-to-none lead in the National League Division Series, having held on for a critical 4-2 victory.

Can’t argue with those results.

“I get it,” Gallen said afterward. “It's October. If that's what he felt like was going to put us in the best position to win, I'm fine with it, and I think it worked out.”

Gallen, of course, would’ve preferred to keep pitching. But after Max Muncy and J.D. Martinez recorded consecutive one-out singles, the Dodgers brought the tying run to the plate with a trio of lefty hitters due up. The chess match was on.

“Zac -- I felt like he had maybe 10 to 15 more pitches, and if it was the middle of July, I would have 100 percent let him continue moving in that direction,” Lovullo said. “But you start to add and subtract, and you're counting batters. I think the reason why we won this game is because we didn't turn the lineup over a fifth time. Our pitchers went out, did a great job.”

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Lovullo called for lefty Andrew Saalfrank, knowing that would force the Dodgers to dip into their bench. They did exactly that, pinch-hitting with righties Chris Taylor and Enrique Hernández. Things got awfully dicey after Taylor reached via walk and Hernández plated a run with an infield single.

The game -- and perhaps the series -- hung in the balance. Saalfrank, a rookie who had pitched all of 10 big league games before he cracked the playoff roster, had the tying and go-ahead runs aboard.

But he recovered, punching out James Outman with a fastball at the knees. Lovullo then called upon right-hander Ryan Thompson, who got pinch-hitter Kolten Wong to bounce harmlessly to first, stranding the bases loaded.

“It wasn't perfect for Andrew, but he bridged it over to the next level of guy that I wanted to use,” Lovullo said. “And Thompson was able to get that big out. So it wasn't perfect, but we did enough to hang on and get the job done.”

When that fateful inning was over, Lovullo had the Dodgers right where he wanted them.

L.A. manager Dave Roberts made a sizable gamble in that pivotal sixth inning. Rightly so, Lovullo said. But in pinch-hitting for Jason Heyward and David Peralta, Roberts removed two key left-handed hitters from the bottom of his lineup -- two lefties who might’ve been useful against the trio of righties at the back end of the Arizona bullpen.

“He did everything he had to, right?” Lovullo said of Roberts. “I think every manager would have done that. There's your one shot. You're trying to make a push there against Saalfrank, a rookie pitcher. But at that point, it's an empty bench. [Catcher Austin] Barnes is the last player, and you can pick your targets and matchups very well.”

Indeed, those three righties -- Thompson, Kevin Ginkel and Paul Sewald -- faced the minimum in the seventh, eighth and ninth innings, respectively. As such, Mookie Betts was left standing on deck when Sewald got Wong to fly out to end the game.

“It’s more frustration upon ourselves,” Dodgers first baseman Freddie Freeman said. “The fifth and sixth innings ... I think a lot of us aren’t gonna be able to sleep tonight.”

That’s when this game was won, as the Dodgers never mounted a serious threat late.

Prior to that sixth-inning bullpen battle, they did manage to put two aboard with one out for Betts and Freeman in the fifth. Gallen proceeded to get Betts to ground out before striking out Freeman looking with a gorgeous 3-2 curveball.

An inning later, Gallen’s night was suddenly done. The NL Cy Young candidate gave way to the rookie Saalfrank and, eventually Thompson, who signed in August after he was released by Tampa Bay.

“It's never a perfect science, right?” Lovullo said. “I can follow the same strategy yesterday and the day before, and it doesn't work. But I believe in it enough, because they've shown me that they can go out there and collect those outs.”

And, sure enough, two improbable high-leverage relievers collected two of the most important outs in this improbable D-backs season.