PHILADELPHIA — When all is said and done, this year’s Diamondbacks playoff run will go down as one of the most magical three-week stretches of baseball in franchise history.

They strung together back-to-back comeback wins in Milwaukee to sweep the NL-Central-winning Milwaukee Brewers. They blasted Clayton Kershaw and the Los Angeles Dodgers in Game 1 on their way to a three-game sweep in which they never trailed. They won a pair of NLCS games, one on a walk-off and one because of a historic, game-tying home run by Alek Thomas that will be talked about for a long time.

But, on Monday in Philadelphia, this unprecedented Diamondbacks playoff run is at risk of ending. Down 3-2 in the series, Game 6 is their first truly must-win baseball game of the year. A loss means they are headed home.

A win, on the other hand, forces a winner-take-all in Philadelphia on Tuesday. And everyone knows what that means.

“Anything can happen in Game 7,” manager Torey Lovullo said. “It’s wide open. It’s a crap shoot.”

The Diamondbacks left Philadelphia six days ago after dropping the first two games of this series, getting outscored 15-3 in the process. Many figured they would not be back.

But, with the aforementioned two wins at home at Chase Field, here they are once again. They would like to make the trip worthwhile.

“We didn’t come cross-country to get our asses kicked,” Lovullo said.

The last time Merrill Kelly faced Aaron Nola was Game 2, which also took place in Philadelphia. It was, by far, the worst game the Diamondbacks have played all postseason. They lost 10-0. They looked like a team that did not belong.

On Monday, they will look to flip the script. And the answers to these five questions will play a significant role in whether or not they are able to do that.

1. Can Diamondbacks’ top hitters overcome series-long slump?

Ketel Marte has been excellent all postseason long for the Diamondbacks. He has a hit in every game and a .372/.400/.605 slash line. His 14-game postseason hitting streak to start his career is the second-longest in MLB history. In this series against the Phillies, he has hit .429/.455/.571.

In order to punch a ticket to the World Series, however, the Diamondbacks will need their other top hitters to contribute, too.

Of the seven Diamondbacks hitters who have started every NLCS game, Marte is the only one with an OPS north of .715.

Christian Walker, who had a 1.096 OPS in the D-backs’ NLDS sweep of the Dodgers, has gone just 2-for-17 in the NLCS with eight strikeouts.

Corbin Carroll, the Diamondbacks’ best player in the regular season, has gone just 2-for-19.

Tommy Pham, who sat out Game 5 in favor of Pavin Smith, went 1-for-13 with six strikeouts in the first four games of the series. He is back in the lineup, hitting fifth, for Game 6.

When asked about the Diamondbacks’ struggles on offense, manager Torey Lovullo toed the line between tipping his cap to Phillies pitchers and expecting more from his hitters.

“I want to give credit where credit is due,” Lovullo said. “The Philly pitchers, especially their one, two … have been really, really effective against us. It’s a mixture of pitches. It’s keeping us off balance. It’s a good pitching plan, attacking zones that might be certain limitations for certain hitters. So that’s A.

“Then, B — and this is where I hold every one of us accountable — I think we’re just making some poor swing decisions. I think we’re chasing certain counts.

“We have to remember that, in order to get a certain pitch that you want to square up, you have to maybe get into the count, get some count leverage, have seen the pitch, know where it’s going to start, know where it’s going to land and then effectively determine where it’s going to be so you can barrel it up.”

The Diamondbacks will not necessarily need all of their best hitters to put up big numbers on Monday, but they will all but certainly need someone outside of Marte to step up.

2. can the Diamondbacks contain Kyle Schwarber?

To say that Phillies designated hitter Kyle Schwarber has had a nice series would be an understatement.

In 22 plate appearances, Schwarber has gone 7-for-17 with five homers, one double and five walks. That works out to an 1.898 OPS.

“It is unbelievable that every mistake that we make,” Lovullo said prior to Game 6, “it’s not a single or a roll-over or a weakly hit ball. It’s going out of the ballpark. We just can’t make mistakes to him right now. That’s what happens when a Major League hitter gets locked in.”

It may come as a surprise that Schwarber struggled in the two playoff series prior to this one. He went 2-for-8 with five strikeouts against the Miami Marlins in the Wild Card Series and 3-for-21 in the NLDS against the Atlanta Braves.

Schwarber has developed something of a reputation as a postseason performer. He has a career .931 OPS in the playoffs in 251 plate appearances, including his similarly impressive .400/.471/1.000 slash line in the league championship series for the Phillies last year.

“I don’t know how to stop him,” Lovullo said. “We just can’t make mistakes. We know there’s holes in there. Every hitter has a hole or two. We just can’t get it to the right spot at the right time, but we’re going to try like hell today to do that.”

3. Will Diamondbacks’ baserunning prowess become a factor?

Much has been made of the Diamondbacks’ lack of activity on the bases in the series. They have just one stolen base, the fewest of any of the four teams in the league championship series.

The Phillies struggled to contain the running game as a team during the regular season, but they made some adjustments down the stretch and in this series that seem to have paid dividends. Diamondbacks speedster Corbin Carroll has yet to steal a base in the series.

“Teams know that I run,” Carroll said. “Philly has done a good job of just making their pitchers be pretty quick to the plate.”

For Carroll and the Diamondbacks, it comes down to a simple math problem. Phillies catcher J.T. Realmuto has one of the best pop times in the majors. Phillies pitchers have been quick to the plate. The Diamondbacks have taken a cautious approach accordingly.

“What I’ve got to remind myself,” Carroll said, “is I’m doing my job. By him being quicker to the plate, by changing his tempo, the hope is that there is an extra ball or two over the heart of the plate for the hitter to get the job done.”

To this point in the series, the Diamondbacks have been unable to capitalize on any such mistakes. Lovullo said that is a point of emphasis for Game 6.

“If the pitchers are so concerned and hearing the black noise over their shoulder,” Lovullo said, “we’ve got to be ready at home plate to take advantage of some mistakes out over the plate.”

While the Diamondbacks will continue to be careful to avoid an out on the bases, Lovullo also said that he would like to get the running game going. We will see if that happens in Game 6.

4. How will the Diamondbacks handle the Phillies’ lineup the third time through the order?

The Diamondbacks have allowed runs early and late in these NLCS games, but figuring out how to handle the Phillies’ lineup the third time through the order has been a particular challenge.

“At this point in time,” Lovullo said prior to Game 6, “it’s the part of the job that’s giving me the most anxiety, paying attention to what’s happening inside of the game for the third at-bat.

“I leave somebody in and he gets hit, and they’re, like, ‘Why are you leaving him in?’ I take somebody out before he gets hit, and they say, ‘You’re crazy for taking him out.’

“I’ll be mindful of it, and I will pay attention to every swing that every player takes leading up to those third and fourth at-bats.”

So far, only the Diamondbacks’ top two starters, Zac Gallen and Merrill Kelly, have been allowed to face the top of the Phillies lineup a third time. The results have not been good for them, nor for the Diamondbacks relievers who were given the same task.

In Game 1, the Phillies scored a run off Zac Gallen on a Bryce Harper walk and a J.T. Realmuto RBI single the third time through.

In Game 2, Merrill Kelly had retired seven straight hitters when Phillies lead-off man Kyle Schwarber homered in his third at-bat to lead off the sixth inning. Kelly retired the next two hitters, at which point Lovullo turned to lefty reliever Joe Mantiply. Mantiply struggled, and the Phillies wound up scoring four runs in the frame.

In Game 3, Brandon Pfaadt was pitching extremely well when Lovullo opted to go to lefty reliever Andrew Saalfrank to face the top of the Phillies’ lineup for the third time. Saalfrank walked two of the three hitters he faced, and the Phillies scored a run as a a result.

Game 4 had a different dynamic since the Diamondbacks used a bullpen game, but the trend continued in Game 5, when Gallen gave up homers to Schwarber and Harper the third time through before being removed after the sixth inning.

In spite of the homer Schwarber hit in his third at-bat against Kelly in Game 2, it appears that Lovullo is willing to stick with him in that spot, depending, of course, on how well he is pitching and how many pitches he has thrown.

“[Kelly] can go fastball, cutter, changeup first time around,” Lovullo said. “He can add in a slider the second time around. All of a sudden, he pulls a curveball out, and he just starts adding more ingredients into his outing through the course of the outing.

“You might not get a look at a pitch or two until your third time, and that helps him be creative in navigating that third time through the lineup.”

5. Can Diamondbacks’ back end relievers continue dominance?

A lot of things have gone wrong for the Diamondbacks in this series, but one that has continued to go well is the performance of their back end relievers, specifically closer Paul Sewald and setup man Kevin Ginkel.

In six appearances in the playoffs, Sewald has tossed six scoreless innings with nine strikeouts and only one walk. Opposing hitters have hit just .143 against him.

Of the Diamondbacks’ seven postseason wins, five have ended with Sewald on the mound locking down the save. One of the others ended with a Marte walk-off single that followed a scoreless top of the ninth by Sewald.

Ginkel has been similarly spectacular in the playoffs. In 6 1/3 innings, he has allowed no runs on five hits with 10 strikeouts and only two walks. Like Sewald, he has pitched in all but one Diamondbacks postseason win.

If recent trends hold, a Diamondbacks win on Monday would likely come in the form of a close game, and Sewald and Ginkel will be needed to seal the deal. No reliever is perfect, but they effectively have been so far in the playoffs.

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Top photo: Rob Schumacher/The Republic