World Series or bust? The surging Phillies should know that answer by the time they leave Arizona.

In October of 2023, the Diamondbacks dashed the Phillies’ dream of winning consecutive pennants.

In September of 2026, the Diamondbacks will serve as a benchmark as to whether these Phillies even have a chance of achieving what the 2023 Phillies came so close to achieving.

Hard to believe, Harry.

A month ago, as the Phillies foundered on the edges of relevance, none of this seemed to matter much. Today, the Phillies have found an identity grounded in smart at-bats, a solid starting rotation, and unexpectedly competent defense. Suddenly, what seemed like a wasted season through four months has transformed into a season of hope and expectations.

As in, if the Phillies are playing this well now, there’s no reason to think they can’t win their first World Series in 18 years.

We’ll know better by dinnertime Wednesday.

The Phillies on Monday night begin a three-game series in Arizona that could determine whether the Phils host a wild-card series in October. The D-backs lead the season series after winning two of three in Philly in April.

As this series begins, the Diamondbacks hold the final wild-card slot but stand 4 1/2 games behind the Phillies. The Phillies are tied with the Cubs, but the Cubs won six of seven against the Phillies in the April games that exhausted the teams’ head-to-head matchups. Should the Diamondbacks surge and the Cubs stall, there’s a chance this week’s results provide the tiebreaker that gives the Phillies the top wild-card spot, the No. 4 seed in the National League playoffs, and home-field advantage over No. 5 that comes with it.

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Of course, the Phillies can render these scenarios obsolete if they clobber the Diamondbacks, pass the Cubs, and maybe even catch the Braves for the NL East title, in which case tiebreakers won’t matter. But the Braves lead by five games with 25 to play, so that seems a bit much to ask.

For the moment, it’s more important to judge whether the Phillies can play excellent baseball on the road against a team that is 13-8 against them since Game 3 of the 2023 NLCS.

The magnitude of the lows might skew the emotions, but the lows against the Diamondbacks seem to be lower than most of the other lows this Harper-Wheeler-Schwarber edition of the Phillies have delivered since 2022.

It begins with that 2023 NLCS, when the Phillies’ bats deserted them and they lost Games 6 and 7 at home. The Phils haven’t won a season series since, and their first meeting this season did not portend favorably.

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The Phillies struck out 16 times against the Diamondbacks on April 10, 15 games before the Phillies fired manager Rob Thomson and promoted new bench coach Don Mattingly to interim manager. The 16 Ks remain a season high, part of the 8.8 strikeouts per game that was among baseball’s worst rates.

Now, though, they’re striking out 2.5 fewer times per game, the second-best rate in baseball. It is the most promising stat of a slew of numbers that indicate that this Phillies team might even be able to topple the Dodgers in the postseason.

If it’s hard for you to believe, that’s completely understandable. Even in the middle of their recent nine-game winning streak, their longest in four years, the Phillies supplied little real reason to believe they might make another long run into October.

Shortstop Trea Turner’s Season from Hell continued. The bullpen remained unreliable. And the two best pitchers weren’t the two best pitchers.

Things change.

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Struggling aces Cristopher Sánchez and Zack Wheeler just combined to allow one run over 13 innings Saturday and Sunday against the Angels. Which, of course, makes them formerly struggling aces Cristopher Sánchez and Zack Wheeler. Add in Jesús Luzardo’s seven shutout innings in Seattle on Aug. 26, and that’s one run allowed for the Big Three in their last 20 innings.

That’s just the icing.

Consider the continued efficiency of No. 4 starter Aaron Nola, who’s on a six-game heater, and rookie Andrew Painter, who’s been better than a No. 5 in five of his six starts since his recall from the minors, and the Phillies transform from Lost Cause to Title Contender.

They’ve won 13 of 15 games, six of those wins on the road, three of the last five in their last at-bat.

Oh yeah.

The hitting.

Since three-time batting champ Luis Arráez played his first game Aug. 4 just after Dave Dombrowski’s latest deadline magic, the Phillies lead Major League Baseball with a .272 batting average and are tied with the Red Sox for the lead in on-base percentage, at .353, improvements of 35 and 48 points, respectively; their .305 on-base percentage was third-worst. In that same span they lead the National League with 100 walks. They are averaging 5.5 runs, an improvement of more than a run per game.

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Since Arráez slid into the cleanup spot they are 16-7, have gone from eight games above .500 to a season-high 17 games above .500, and are tied with the Cubs atop the National League wild-card standings.

Arráez’s arrival shuffled the defense, an unintended consequence that reaps daily rewards. Arráez is best at second base, so Bryson Stott moved to third base, where he has proven to be the best third baseman in baseball since the move. Third baseman Alec Bohm pushed first baseman Bryce Harper to right field, where both are at least average, whereas neither was average in their previous positions.

In the middle of it all, Harper has reached base in 32 consecutive games, a career best. A two-time MVP in the midst of his most efficient stretch of offense would be the biggest news of all on a team that didn’t have so much to win, so much to lose, and so much scar tissue since their NLCS collapse in 2023.

Still.

Listen, the Phillies aren’t the best team in baseball. They still make too many baserunning errors. Wheeler is still walking too many batters (three more Sunday). The bullpen is still thinner than the Arizona atmosphere.

But if they take off from PHX on Wednesday night with two or three wins in hand, maybe overtake the Cubs if the Brewers beat up on them the next four days, and sustain this surprising run of professionalism and competence, then yes.

Believe it.

World Series or Bust.