The Capitals dominated the Golden Knights on Saturday night, giving fans plenty to cheer for. (Ricky Carioti/The Washington Post)

Now is the time for Washington fans — and Capitals fans especially — to get as excited and emotional as they want, provided nobody falls off a roof. What you think is happening is probably really happening. Anyone who makes predictions is banished. Watch, root or go crazy. Just don’t predict. As for thrilled, just go for it.

For the Capitals themselves, however, this is the time to do perhaps the most difficult task of mental and emotional preparation in sports — channel that same excitement and emotion that millions feel but transform them into focus. Celebrate goals. But then reset every neuron toward attention to the moment, to detail.

“This series has excited the fans,” said Alex Ovechkin, whose 14 goals this postseason has been topped only once in the Stanley Cup playoffs since 1996. “But again, it’s only two [wins]. Move forward and don’t think about it too much.”

These Capitals, who lead the Stanley Cup finals two games to one over the Vegas Golden Knights, will do that job. They are different from their predecessors, profoundly different in competitive temperament. That does not ensure a happy outcome. But it is an essential prerequisite to it. You can watch the Caps now with your heart in your chest, where it belongs, not in your throat. It took four years under Coach Barry Trotz for the Caps to learn how to breathe under pressure. But they have.

That means you can, too.

“There’s a lot of pride in this D.C. area. . . . [But] sometimes before the games even begin, there is anxiety,” Trotz said after a 3-1 win in Game 3 on Saturday night. “We’ve gotten past that as a group. And hopefully as a community . . . I think it will galvanize all the teams in this area. I know the baseball guys are all watching us.” (Nationals Manager Dave Martinez may sleep in his Caps cap.)

The “tell” on Game 3 may have come afterward when Golden Knights Coach Gerard Gallant came close to saying what you never hear any coaches say mid-series — this thing isn’t going our way.

“Just get ready for the next one. That’s all you can do. They were the better team. They deserved to win,” Gallant said. “I thought we played better than we did in Game 2. But in the first period, they set the tone real good.

“We were more competitive around their net. It was a close hockey game,” he continued, then added, as if hockey’s appealing tendency toward candor demanded it, “[Goalie Marc-Andre] Fleury was the difference for us — to stay close.”

To stay close? Is this just playing possum or hiding your cards?

The Caps certainly sense a trend in this series — steadily toward them.

“You just have to throw out Game 1. Everybody was out of their minds,” said Trotz, mentioning the volume level before that 6-4 Vegas win and the joy of both teams — the Biggest Underachievers Imaginable finally playing for the Cup against the Biggest Overachievers Unimaginable. “Probably Gallant would say the same. You didn’t see the true teams, even though you saw an incredible game.”

Braden Holtby, the quiet Caps goalie whose demeanor and goin’-up-the-country lifestyle evokes a mellow peace marcher from 50 years ago, definitely feels the same vibe. “Game 1 was a strange game. We were off. Myself, too. . . . We did a good job of leaving it at that,” Holtby said, reflecting the Caps’ hard-won new ability to compartmentalize games — good or awful — then start again fresh.

“Now everyone is pitching in in every way,” said Holtby, who appreciated the 26 blocked shots in front of him Saturday night, 15 of them in the first period.

Then Holtby gave an illustration of the deep respect for detail, for pride in hockey craftsmanship, that the Caps so often and so infuriatingly have lacked in past. It’s not just the number of sacrifice-my-body blocks that matters; it’s where every defender in front of him has positioned himself to provide a human wall, shielding half the goal while leaving the other half clear so Holtby can see shooters.

“We are creating the right layers [of defenders]. They understand what my sight lines will be,” Holtby said, “and they take away the other half.”

The scene in Game 3 was abnormal for a Caps playoff game in two important ways. First, perhaps no local crowd, at least to my eyes and ears, has supported a local team so loudly and viscerally since the Redskins played in three NFC championship games at RFK Stadium. The crowds at Nationals Park for three Game 5s probably came close. Is this a D.C. thing? The magnitude of the game exponentially increases the ability of local crowds to loosen up and get nuts?

The Red was rocking before Joe Gibbs, a great NFL pep-talker, started leading “Let’s go, Caps” cheers, all projected on the huge overhead screens. Good luck to Vegas trying to match a jubilant three-time Super Bowl winning coach with its aimed-at-age-8 sword fights. D.C. tops Vegas in showmanship? Strange days.

“We thrive off the support. We love our fans,” defenseman John Carlson said. “They’ve stuck with us through a lot. They deserve us to get there.”

Then, in the next breath, Carlson touched on the second unusual aspect of the tenor of this series — the sober, flatline mood inside the Caps’ room.

“We’ve got a long way to go,” he said.

What, two wins is a long way to go after you have played 104 games this season and are just two wins from whatever-that-thing-is?

Yes, exactly. Because the Capitals own all of the records for getting ahead of themselves, being carried away to sea by the emotional riptides of the moment and even — year after year — giving serious, lengthy answers to that lets-see-whether-they will-bite question: “How would it feel if . . .” I wanted to scream “Stop!” every year that I hear it. Now, new Caps and a new answer — a polite “No answer.”

Erase the “if,” then talk about it.

“We’re just putting our head down, focusing on Game 4,” Holtby said.

They better. Because these Caps will get “if” questions — from the media and from places inside their own brains that are not doing them any good — until somebody is hugging the Stanley Cup and giving it a victory lap.

When you are the only franchise in any sport that has squandered two-win leads in 10 postseasons, you’re never safe. Luckily for the Caps, they are not a “franchise.” They are not an extension of the history of their sweaters. They are an actual team — this team, with its culture and character.

The center of that culture change, which has taken four years to instill, is Trotz, and the key to the buy-in has been Ovechkin’s commitment to team, his focus on dirty details, while letting talent and creativity show up when they will.

“Game 1 was the only game in our last 15 or so when we didn’t play our way. . . . But momentum from game to game? I don’t think there is any. Every series we’ve been in shows that,” Trotz said, underlining again that each game is separate and each moment within that game the only useful focus.

“We are getting stronger and finding our game against a very strong opponent,” Trotz said of favored Vegas. “Of course, they will make adjustments.”

If the Caps keep this up, it is Washington — its attitude toward its place in sports and the attitude of its teams toward how they go about winning — that will require an “adjustment.” Not that anybody’s complaining.

For more by Thomas Boswell, visit washingtonpost.com/boswell.