In the haze of the unknown, everybody on and off the ice was sure of only one thing about the Utah Mammoth in Game 1 of their first-round playoff series against the Vegas Golden Knights: They have a slew of younger players who were getting acclimated to their initial steps in a bump-and-run for Lord Stanley’s Cup.

Question: Would they rise to the occasion or would they shrink away?

Answer: They’d do neither.

Those young ones, indeed, would have to learn to walk before they ran, before they skated. Ironically enough, skating hard and fast is one of the technical advantages the Mammoth were supposed to have over the more experienced Knights.

Nate Schmidt, one of the Mammoth’s playoff veterans, a vet who won the Cup last season with the Florida Panthers, spoke emergent hope to seasoned power when he suggested that maybe, just maybe: “Ignorance is bliss.”

He added: “We have a lot of youth, a lot of young legs. … I love the idea that our guys are quick, they’re fast, they’re in this time of year for the first time. The youthfulness is something that I’m excited to see.”

He might have been less excited to see it as the Mammoth stumbled to defeat on foreign ice on Sunday night by the count of 4-2. An empty-net goal for Vegas near the end made that margin larger than it actually was.

As was evidenced time and again in this game, there is a different tone and texture to NHL playoff hockey, a heightened intensity and urgency that can bring out the best in a team — and that was exactly what seemed to be happening for the Mammoth through two-thirds of the game. That last third, however, killed them.

An old familiar saying, often erroneously attributed to the White Rabbit in Lewis Carroll’s “Alice in Wonderland,” goes like this: “The hurrier I go, the behinder I get.” Something the Mammoth had to keep in mind. Go fast, but not frantically fast.

Even as the Mammoth attempted to use their energy, speed and aggression to their favor, another component reared its head, as expected, in Game 1: physicality. While kids like forwards Dylan Guenther and Logan Cooley hadn’t absorbed roughed-up postseason play, at least not at the NHL level, both said they were focused on and prepared for it.

“That’s playoff hockey,” Guenther said.

And, yeah, there were big hits, bloodied lips, sloppy sticks, head-butts, scrums, shoves and fisticuffs early and late. Nobody shied away.

Still, Mammoth defenseman Ian Cole, another graybeard and a winner of two Stanley Cups when he played for Pittsburgh, said: “Hockey is hockey. … This is important hockey.”

He said careless penalties, gifted opportunities to an opponent cannot be afforded in the postseason. More on that in a minute.

Schmidt and coach Andre Tourigny both proclaimed beforehand that their team is exactly where it should be, where it deserved to be, squarely in these playoffs — and that a single outing, be it positive or negative, doesn’t completely undo or underscore the fact. Come what may, there is work straight ahead.

And now, with the Mammoth down a game, they turn straight into that work with lessons learned and adjustments to make.

Utah had good chances in Game 1 pretty much from start to finish, but Vegas goaltender Carter Hart stopped all but two of those shots. The Mammoth’s Karel Vejmelka was busy, too.

Through the middle-to-back section of the first period, the Golden Knights controlled the puck, until a couple of roughing calls opened the ice with two minutes of four-on-four play. No advantage gained there. Neither team could capitalize.

Later, even when the Mammoth had power-play opportunities near the end of that opening period, there were no goals. And then, after a sweet pass, Cooley went down on one knee to slap home a goal at the close of the first.

It didn’t take much time, no more than that, to realize this series is going to offer some information about the Mammoth, as well as good hope for exciting entertainment, alongside a good dose of hardcore hockey.

A Vegas goal followed to equalize, testing the Mammoth’s resolve.

It took about a minute for them to show that resolve, when goaltender Hart spun behind his net to reset before the puck was nudged into the goal by Kevin Stenlund — 2-1, Utah.

Chances continued for the Mammoth, without a score. Same for the Golden Knights. Both tenders were making saves and saving their teams or at least keeping them in the game.

Into that third period, the Mammoth played loosely but somewhat dangerously, as Vegas repeatedly controlled the puck. Utah tried to continue doing what it had done successfully earlier, namely advance the puck, pressuring Hart and the rest of the Vegas defense.

But then, a tripping penalty by Alexander Kerfoot handed the Golden Knights a power play, and the Mammoth, who had struggled at times at killing such advantages over the back half of the regular season, struggled again here, as the Golden Knights’ Mark Stone got a shot past Vejmelka.

It was exactly what Cole had previously warned his teammates about — committing a senseless penalty that could alter a playoff game’s momentum.

A subsequent goal by Nic Dowd enabled Vegas to take the lead, in large measure, again, by way of possessing the puck. Chasing those possessions appeared to tire out Utah from stem to stern. Thereafter, the Mammoth simply couldn’t get the goal they needed. The aforementioned empty-netter finished the scoring for Vegas. A couple of scrums finished the action.

Ultimately, Utah capitulated at the end. It did not wholly collapse.

Either way, a mostly strong effort by the Mammoth was swamped when it mattered most by Vegas’ disciplined play and an onslaught of shots. How Utah’s youngsters respond, in the run-up to Game 2, is the question with an unknown answer now spinning across the ice.