Chicago Cubs' Miguel Montero (47) celebrates after hitting a grand slam during the eighth inning of Game 1 of the National League baseball championship series against the Los Angeles Dodgers Saturday, Oct. 15, 2016, in Chicago. (AP Photo/Charles Rex Arbogast) (Charles Rex Arbogast/AP)

From time to time, modern baseball can seem to be whittled down to a simulation, models that can be run through time and again to figure out probabilities. In the playoffs, in particular, there is no scenario front offices and managers have not considered. If this, then that. Over and over, until there’s nothing left to do but play.

The Los Angeles Dodgers faced a series of moments like this Saturday night in the first game of the National League Championship Series. Their manager, Dave Roberts, responded by issuing two intentional walks in the eighth inning, one to a .230 hitter who was just 2 for 15 in the postseason at that point, the other with runners on first and second, loading the bases on purpose in a tie game.

“I’d never seen that before,” Chicago Cubs catcher David Ross said.

Nor had he seen what followed. In that moment, put away the charts and the laptops, replace a simulated game with a real one. The Cubs won because Miguel Montero, who has put aside the frustration associated with being relegated to a role as a backup catcher, drilled an offering from Dodgers reliever Joe Blanton over Wrigley Field’s right-field wall, an unexpected pinch-hit grand slam that came in an unconventional eighth inning and led to an 8-4 Cubs’ victory.

“The cat and mouse between managers only goes so far,” Ross said. “Sooner or later, the players have to step up and perform.”

Montero did. It’s odd, in a game in which so much happened — Javier Baez turning a botched squeeze play into a steal of home for the Cubs, Adrian Gonzalez delivering a two-out, game-tying, two-run single off lethal closer Aroldis Chapman for the Dodgers — that everything was distilled to that eighth inning. It took a lot to get there, with a 3-3 tie. It took more to decide it.

Montero, who has seen his time behind the plate dwindle as Manager Joe Maddon has turned to a three-man machine that includes Ross as the veteran and Willson Contreras as the rookie, was a central piece.

“With three catchers, you have to man up and get the best out of it,” Montero said, and he did, turning an 0-2 slider from Blanton into a no-doubt bomb.

But really, in a way, the most important character in that bottom of the eighth was Chapman.

“As the game was tried, you’re trying to figure out a way to win it,” Roberts said. “And what’s the best way to win that game? It’s to get him out of the game. I felt that if we did that, then the game was ours.”

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Roberts got Chapman out of the game. The Cubs won anyway.

To start: Chapman appeared in the eighth, not his accustomed frame, because Mike Montgomery and Pedro Strop had combined to load the bases with no outs as the Cubs nursed a 3-1 lead. The initial results: overpowering strikeouts of Corey Seager and Yasiel Puig. But then, as Maddon said, “A really good hitter gets a base hit up the middle.”

That hit, from Gonzalez, deflated the Wrigley crowd of 42,376. The Cubs are the best team in baseball, and they are favored in this series for very real reasons. But in moments like this, the club’s history — repeat it again, no World Series titles since 1908 — envelops the old stands.

“You hear it,” third baseman Kris Bryant said. It’s just a natural part of life here. But Chapman did well to get Yasmani Grandal out to end the eighth and keep it at a tie game.

That’s when the Cubs went to work, and got Roberts scrambling to keep up. Ben Zobrist led off the bottom of the eighth with a double, and after an out, Roberts went to his matchup game. Cubs right fielder Jason Heyward had about as disappointing a season as any big-time free agent this year — he signed an eight-year, $184-million deal and then hit the aforementioned .230. But he is a left-handed hitter. So even though he was just 3 for 15 lifetime off Blanton, Roberts intentionally walked him to get to Baez.

“In that situation,” Roberts said, “you got to walk Heyward.”

Baez is about the most dynamic player in the postseason, but the strategy initially worked. He flew out harmlessly to right. That left pinch hitter Chris Coghlan as the potential last out of the inning. If Blanton could retire him, the game would go to the ninth, tied.

This is where Chapman becomes the central character, even as he rested on the bench. His spot was after Coghlan’s. In a tie game, Maddon couldn’t afford to let Chapman hit. Roberts knew it.

Roberts called for the intentional walk of Coghlan, who also happened to be 8 for 17 off Blanton in his career.

“I probably would have done the same thing,” Maddon said.

So there it was, bases loaded, and Montero now hitting for Chapman.

“That’s what you live for,” Montero said.

Blanton, as he does, fed him sliders. He fouled off one, then swung through another.

Down 0-2, simulate this: Blanton came with his third consecutive slider. And there it went, into the black sky. Baez, back in the video room examining one of his at-bats, heard the explosion.

“You could feel the roof moving from the fans,” he said.

Dexter Fowler followed with a solo shot and Blanton was done, an uncharacteristically shaky outing for a pitcher who has been so important to the Dodgers.

And so the NLCS is under way. It has been played out in simulations and models, and they have shown what is probable to happen. But tune in Sunday night. Because in the late innings, one man will have a bat in his hands, and another will stand 60 feet, 6 inches away, and there’s no telling what might happen next.