PHILADELPHIA -- When Merrill Kelly returned to the dugout following the bottom of the fifth inning in National League Championship Series Game 6 on Monday, having just whiffed Bryce Harper to record his eighth consecutive out, D-backs manager Torey Lovullo was there to greet him. Lovullo offered a handshake, as is customary when a starter is done for the night.

Loosely grabbing his boss’s hand, Kelly could not hide the look of wariness on his face.

“He wanted to go more,” as D-backs outfielder Tommy Pham recalled it. “He was fighting with Torey in the dugout. I was like, ‘Let him!’”

Lovullo did not let him. Eventually, Kelly accepted his fate, grabbed his equipment and returned to the clubhouse, shaking his head and muttering most of the way.

This is how the D-backs have arrived on the verge of the World Series, forcing NLCS Game 7 with a 5-1 win over the Phillies at Citizens Bank Park. Steadfast in his reliance on data to dictate pitching decisions, Lovullo makes choices that fans and players alike can find difficult to digest.

Those decisions have also largely proven effective.

“I feel like he’s done it all postseason,” D-backs outfielder Corbin Carroll said. “You’ve got to give him credit. He’s going with how he feels and it has not come back to bite us yet.”

More than feel, Lovullo uses information to guide his decisions -- the propensity of Brandon Pfaadt to become more hittable the third time through a batting order, for example, which guided Lovullo’s controversial move to lift the rookie after only 70 pitches in Game 3. Following that win, Lovullo jokingly referred to himself as an “idiot.” He admitted that he often second-guesses his decisions, even when they work.

Add this one to the pile. There was plenty of reason to believe Kelly, given a crack at the sixth inning Monday, would have been just fine. Relying on a six-pitch mix, Kelly didn’t throw any of his offerings even 30 percent of the time. Instead, he used pinpoint location and relentless speed changes to baffle the Phillies.

“He didn’t really miss very many spots to me,” Phillies outfielder Nick Castellanos said, “and the pitches he did throw over the plate had pretty good movement.”

In the first inning, Kelly mostly threw sinkers and four-seam fastballs, especially to Philadelphia’s left-handed hitters. Those became cutters, changeups and breaking balls later in the evening. The only damage Kelly allowed came on a one-out Brandon Marsh RBI single in the second inning, following J.T. Realmuto’s leadoff double. When he induced Bryson Stott to hit into a fielder’s choice for the second out of the third inning, Kelly began his run of retiring eight in a row.

The final three came in order in the fifth. Leading off was Kyle Schwarber, whom Kelly had walked twice previously in the game. This time, he fanned Schwarber on a 3-2 curveball over the heart of the strike zone -- the first curve Schwarber had seen all game. Kelly dispatched Harper with a nastier curve to end the inning, then came off the field to encounter Lovullo waiting at the bottom of the dugout steps.

“I think partly why I was upset right there was I was kind of just taken off guard by it,” Kelly said. “I just went through their top three, punched out two of them. Ninety pitches through five, I'm thinking I’m for sure going back out for six. When I came in and saw his hand out for the handshake that I was done, it kind of just took me by shock more than anything.”

Before the game, Lovullo suggested that Kelly’s diverse repertoire might inform a decision to use him longer than he would other starters. But Kelly’s high early pitch count, combined with what Lovullo believed was a deterioration in the quality of his stuff, prompted the manager to make another unpopular decision.

Expect more of the same in Game 7 with Pfaadt on the mound, Zac Gallen available in relief and everyone else other than Kelly ready to go. Quick hooks and analytically driven decisions will be prevalent in both dugouts.

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In Arizona’s, the manager has plenty of recent experience with it.

“Some of the guys who have played in the postseason a little longer than me have kind of talked about the momentum of the postseason, how it’s important to not kill that by maybe taking a pitcher out that’s doing well,” Carroll said. “But I think he’s threaded that needle pretty well.”