For five months, from May 24 when they started to win, until Oct. 23 when they took a 2-0 lead on the Houston Astros in the World Series, the Washington Nationals played as well as they possibly could. They ignored or improvised around their weaknesses, took off on an 84-40 whirlwind ride that included a remarkable 18-2 stretch that ended with that win over Houston in Game 2, a splendid crescendo that included clutch hitting and star starters making crucial appearances out of the bullpen.

The past two days have seen the Nats’ lead in this World Series erased, with Houston’s 8-1 thumping in Game 4 knotting the series. The calendar says it’s October, but it feels suspiciously like May.

From the great heights to which they climbed, the Nats appear to have broken the first rule of tightrope walking — don’t look down.

Before you could say, “Washington is in the World Series!” the Nats returned home, found themselves neck-deep in well-deserved love, and, trying to please, trying perhaps too hard, they looked down.

Hot hands don’t last forever. Resilience is a virtue, but you can’t order a fresh supply online. Now, in a 48-hour blink that has been a slap in the face to both a team and its love-struck town, the Nationals have reached a crisis point that requires them, at this moment, to somehow return to who they were for those five months — not the team that appeared on their home field the past two days.

When the World Series finally arrived in Washington after 86 years, the Nationals and their fans certainly got to see something special. But they hated it.

Jose Urquidy, a 24-year-old rookie with two career wins in the big leagues, outpitched the Nats’ $140 million free agent, left-hander Patrick Corbin, in Game 4.

Urquidy, who underwhelmed hitters at Class AA Corpus Christi and Class AAA Round Rock this season, rose to the moment Saturday night at Nationals Park, pitching five scoreless innings and allowing just two hits. Asked to provide the first two, three or (please) four innings of a bullpen game for Houston, he ended up earning a win.

Corbin, in his most important game as a National, gave up two runs before he got two outs and had the Nats in a 4-0 hole by the fourth inning. Whatever pressure the World Series stage, and a loud Nationals Park crowd, might have placed on Urquidy, evaporated thanks to Corbin’s generosity.

The Nats were trailing 4-1 when forced to call upon the lesser components of their (shhhh) b-u-l-l-p-e-n — if you spell it, the small children can’t be frightened. The parade of relievers led, in short order, to Alex Bregman’s seventh-inning grand slam.

“In Game 3, we stopped the bleeding. Then we played well tonight. We want to keep rolling. We’re fired up. It’s really exciting,” said Bregman, the slammer. “It’s a great atmosphere here. The fans are into the game, [but] it’s good to know we’re going home.”

This loss, the second straight in which the Nats barely showed a pulse save for defensive brilliance from Victor Robles and Anthony Rendon, may have provided a pivotal shift in momentum.

Not only did the virtually unknown Urquidy beat Corbin, one of the Nats’ Big Three who allowed four runs in the first four innings, but the entire Nats lineup was tight and pressing, swinging at pitches early in counts with men on base, and, time after time, swinging through fastballs over the meat of the plate.

There’s a name for this October phenomenon. It’s called pressure. The Nats have barely felt it this month — if they have, they’ve ignored it or played above it. But it’s got them now. They’ve looked around and seen where they are — high in the baseball sky with a glorious view of a World Series title, but also with no net beneath them and a gifted, cocky Astros team anxious to push them off that high wire.

Urquidy and the Astros bullpen pitched well in the past two games. But not that well. The Nats team that hung defeats on Gerrit Cole and Justin Verlander, back-to-back, in Games 1 and 2 was, usually, fairly loose by World Series standards and, often, having F-U-N.

The Nats are not having F-U-N now. If you see a trail of sawdust from the Nats dugout to home plate, it’s from Washington hitters squeezing their bats so tight they’re turning to dust.

The beneficiaries are worthy Astro gentlemen such as Urquidy. You don’t often see a World Series game in which a well-regarded prospect but one who had a 4.09 ERA at Class AA Corpus Christi and a 4.63 ERA at Class AAA Round Rock bamboozles a tense lineup that was the second-highest-scoring outfit in the majors since May 23.

Urquidy, who pitches at the top of the strike zone, while occasionally “showing” low pitches, has challenged hitters at all levels in the past year, including pitching for Mazatlan in his native Mexico last winter (4.50 ERA). With a 95-mph fastball, a couple of clicks above MLB average, and a good change-up, Urquidy has followed a similar pattern at all stops — Urquidy avoids walks but gives up home runs.

The Nats drew no walks. But also hit no homers.

Meanwhile, Corbin allowed two runs before he got his second out. Then he allowed a two-run homer to the Astros’ No. 7 hitter, Robinson Chirinos, in the fourth inning, for a 4-0 deficit.

The Astros had a simple, smart plan: Corbin likes to get ahead of hitters quickly, then get them to chase sliders low or fastballs up or away. So, Houston didn’t let him do it. They swung at the first strike he threw in almost every at-bat, assuming, correctly, that even if they were quality sliders and fastballs that they would also be strikes. Because Corbin barely has a third pitch, usually adding and subtracting a bit to his fastballs and sliders, this approach produced loud sounds.

Corbin and catcher Yan Gomes couldn’t, or didn’t, adjust until José Altuve, Michael Brantley, Bregman and Yuli Gurriel had all ripped hits and two runs had scored. When hitters are this aggressive, there are counter measures, some as simple as treating an 0-0 pitch as if it were 0-1 — meaning you aim for an edge, rather than “getting ahead” and use their aggression to your advantage.

While Corbin has been helpful twice in relief, he has also shown nerves in his first postseason, walking four men in the first inning of his debut, allowing six runs in two-thirds of an inning in a relief outing and running out of gas with a lead in the clinching game of the NLCS.

My stomach, which has reacted on a visceral level while covering 44 World Series, doesn’t enjoy what it is digesting — a team that has done wonderful things but that is very close to curling up in a very tight ball at the very worst time.

Maybe the sight of Max Scherzer starting Game 5 against the mighty Cole, the Game 1 loser, will click a switch. But changes in momentum and mojo mid-World Series usually happen only once — then the Series simply plays out that dramatic change. Luckily for the Nats, there are exceptions. The Nats have been Team Resilience repeatedly. But this will be their biggest, toughest challenge.

There have been 25 postseason series in which a team won the first two games on the road — as the Nats did. However, on the six occasions when the trailing team ever got to two wins, the record is 3-3. So, by all means, don’t miss a pitch of matches between Cole and Scherzer in Game 5 or Stephen Strasburg, who does not appear to be in a mood to lose this month, vs. Justin Verlander, who is 0-5 in the World Series, in Game 6.

In the World Series, always bet on drama. Always assume that if you believe something, you will be confounded, and for reasons you never imagined. For example, I have thought that the winner of Game 4, in which the Nats had a clear pitching advantage on paper, would win the series. The Nats, of course, will see a 2-2 tie and remember the three times this October when they have already won elimination games, twice with eighth-inning comebacks when the pennies were being put on their eyes and the sheet pulled over their heads for the last time in ’19. Yet they rose.

Often, the most severe challenges in sports actually relax the nerves. Hitting against Cole or Verlander is so hard that if you fail no one requires an explanation — you’re just another victim.

But if you score nine runs off them — as the Nats did in Houston — it is probably because you did not try to do too much and played without pressure because it was assumed by many you’d fail.

It is frequently said in press boxes midseason after wonderful, tense games with marvelous plays that “if this game had been played in a World Series, they’d talk about it for 50 years.” If the first two World Series games played in Washington in 86 years were played on a pair of innocuous summer evenings, you wouldn’t remember them for 50 seconds. They have been that drab.

Unless you are an Astros fan or favor their cause. Then, these were nights of baseball majesty.