When the delirium dies down, when this historic victory sinks in, the Washington Nationals will remember the stakes of a season living on.

They must prepare for another fight, a longer one, against the St. Louis Cardinals. The Nationals are the new kids on the block in their first National League Championship Series, while the Cardinals are the old guard, the establishment, the holder of the most World Series titles, aside from the New York Yankees, with 11.

The NLCS is a place the Nationals have never been, but it is not unfamiliar. This team, as it will tell you, has been playing elimination games since May 24, since the day it returned to Washington at 19-31 and its manager, Dave Martinez, was seemingly destined for the door. The Nationals are not that team anymore. They are the team that got healthy, hit and tied the Los Angeles Dodgers for the best record in the National League after the season’s 50th game (74-38). They are the team that overtook the Dodgers when it mattered most, in the NL Division Series. They are the team that flew to St. Louis on Thursday morning with a chance to put itself in the World Series.

The Cardinals present a serious and immediate challenge to whatever dreams the Nationals have. It might not seem like it, because the NL Central champion won the fewest games of any team in the LDS round (91), but the Cardinals possess traits that make a club difficult to deal with in October.

They have a capable starting staff, a deep bullpen and a solid defense that didn’t make more than two errors in a game all season. They have some experience with catcher Yadier Molina, starting pitcher Adam Wainwright and outfielder Dexter Fowler. They, perhaps most dangerously of all, have confidence. They sprung a 10-run first inning on the Atlanta Braves in their own Game 5 and bounced the NL East champion from the postseason with a 13-1 victory.

The manager, Mike Shildt, embodied the mind-set his team will bring to its series with the Nationals as he stood in the visitors’ clubhouse at SunTrust Park. The 51-year-old usually appears deferential in his cap and glasses, but the hard-charging Tony La Russa disciple emerged in the clubhouse after the game. He delivered an expletive-laden speech that, unbeknown to him, one of his younger players live-streamed on social media.

“No one [expletive] with us. Ever,” he said. “Now, I don’t give a [expletive] who we play. We’re going to [expletive] them up.”

In Game 1, the Nationals will start Aníbal Sánchez and the Cardinals will counter with veteran right-hander Miles Mikolas. The four aces in this series — the Cardinals’ Jack Flaherty as well as the Nationals’ Stephen Strasburg, Max Scherzer and Patrick Corbin — are unavailable because they gave all they had just to get here.

Flaherty started Game 5, and the team decided not to sit him after the explosive first inning to make him available earlier in the series. Flaherty is an NL Cy Young Award candidate, the owner of a 0.91 ERA in the second half who would line up to start Game 3 and, if necessary, a potential Game 7. Braves Manager Brian Snitker compared the 23-year-old right-hander to a younger Scherzer.

Yet for the Nationals, Sánchez might provide an advantageous matchup. The veteran right-hander baffled the Dodgers with his off-speed pitches in Game 3 of the NLDS, and he could do the same to a Cardinals team that has struggled all season with breaking balls and off-speed stuff. The Cardinals have talented hitters, such as first baseman Paul Goldschmidt and left fielder Marcell Ozuna, but they are not a juggernaut. Their on-base percentage, runs scored and home runs were the worst totals of any playoff team, and they are susceptible to simple adjustments. The Braves flummoxed the Cardinals in a Game 2 win while throwing 12 four-seam fastballs in 116 total pitches — something the Nationals could look to exploit with Strasburg’s curveball, Corbin’s slider and Sánchez’s kitchen sink of off-speed weapons.

The biggest questions for the Nationals headed into this series are the availability of Victor Robles, their starting center fielder who is out with a hamstring strain, and Kurt Suzuki, the personal catcher to their top pitchers who left Wednesday night’s game after being hit by a pitch. The Cardinals are healthy after a key piece of their team, veteran infielder Kolten Wong, returned from a hamstring injury that kept him out nearly two weeks. He played throughout the NLDS.

The Cardinals, in some ways, resemble the Nationals. Both teams were hobbled to varying degrees to start the season only to rebound. Both teams rely on mostly veterans with some youth. Both teams are led by old-school managers who deploy flexible utility players (Washington’s Howie Kendrick, St. Louis’s Tommy Edman) and embrace parts of the game that analytics suggest are detrimental. They like sacrifices and bunts. They tied for the NL lead in steals with 116. They talk about run production with the word “manufacture” instead of “math.”

Perhaps the sharpest divide between these teams comes in the bullpen. The Nationals have two truly trustworthy relievers, Daniel Hudson and Sean Doolittle, and a best-of-seven series will make it difficult to conceal this weakness as they did against the Dodgers, using starters in relief and generally not allowing any relievers other than those two to enter in a high-leverage situation. Yet the Cardinals’ bullpen, which had the fifth-best ERA in baseball this season (3.82), looked shaky at times against the Braves.

This is particularly true for closer Carlos Martínez. The right-hander was erratic on the mound and off it throughout the series, and he told reporters he was struggling with the recent death of someone close to him back home in the Dominican Republic. Martínez pitched 1⅓ innings and earned the win in Game 1, then blew a save and took the loss in Game 3. Throughout, he took exception to Ronald Acuña Jr., the Braves’ young star whose demonstrative joy and frustration on the field echo that of Nationals phenom Juan Soto.

This series will be even more contentious with what’s at stake. Each team will use its best, and though the Nationals might have a liability in the bullpen, it might hold up better against a weaker offense. Right now, though, it’s impossible to say. After all, the Nationals weren’t supposed to beat the Dodgers in the first place.

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