LAS VEGAS — As the old saying goes, it’s not over until the fat lady sings. She’s warming up right now, though.

At 5:55 p.m. PDT, it looked like Colorado was going to fight its way back and make it a series. By 7:55 p.m., its season was all but done, as the Golden Knights sent them to the brink of elimination with five consecutive goals to win Game 3 by a score of 5-3 and take a 3-0 series lead.

You could not draw up a better start for the Avalanche. The captain, who missed three regular seasons and battled back to get to this moment, silenced the crowd just 3:21 into the game. Nazem Kadri, brought back to help this team win another Stanley Cup, added a goal of his own four minutes later. Jack Drury, picked up in the Mikko Rantanen trade last season, scored a shorthanded goal 13 minutes in that stunned the Vegas crowd.

Everything was coming up Colorado. Until it wasn’t.

There were signs of it toward the end of the first. Colorado started to get a bit undisciplined, and Vegas’ deadly power play was creating chance after chance. Scott Wedgewood stood tall at the end of the first, but like everyone else on the roster, the rest of the game was a different story for him.

Just 19 seconds into the second, the Golden Knights pulled off a beautiful passing play on the power play that Colorado’s man advantage could only dream of. Bing, bang, boom and the puck was in the back of the net, giving the building life. Panic and the inability to make a play under pressure from the Avalanche saw the Golden Knights add another just a few minutes later.

Uh oh.

Then came the double whammy. Nathan MacKinnon, Colorado’s star center, put his right knee down to block a point shot off the stick of his Team Canada teammate Shea Theodore. He blocked it, but he didn’t get up.

MacKinnon needed help getting to the bench. He would return, but was clearly not 100% or anywhere close to it. The very next shift, those sneaky Golden Knights got away with some interference in the neutral zone on Josh Manson and the man who got away with the crime scot-free was the man who would tie the game up.

As disastrous as the second period was, this was still a tie game heading into the third. A veteran team like the Avalanche has been here before and should have been ready for the moment.

Unfortunately, the other team looked a lot more ready.

Tomas Hertl, who has been reborn under John Tortorella, danced past a soft Sam Malinski’s stick check and beat Scott Wedgewood, making it 4-3. The Avalanche pushed, but it never felt like they were going to get back in this one. Not with a one-legged MacKinnon, no Valeri Nichushkin, and some key players disappearing at even strength. An empty netter sealed the deal for the Golden Knights.

Vegas stuck the knife in Colorado’s back and started twisting it. And the Avalanche just didn’t have a response.

So what went wrong?

“Everything,” Jared Bednar said.

Vegas outworked, out-competed, and just plain outplayed the Avalanche over the final 40 minutes. When the going got tough, the Avalanche collapsed. Throughout the series and again Sunday night, the Golden Knights have gotten key goals at key moments that the Avalanche haven’t, and perhaps just as importantly, key saves that just haven’t been there on Colorado’s end.

No matter what happens the rest of this series, this sure feels like rock bottom.

“(Morale’s) low. As low as it can get, because it’s a big hill to climb,” Bednar said. “The next 24 to 36 hours is for … you’ve got to find a way to get over it, regroup and go again.”

Regrouping may look very differently for these Avalanche. Although they got Cale Makar back, which seemed to give them a temporary boost, they may have to go on without MacKinnon and Nichushkin. It’s a stunning turn of events for a team that, just one week ago, looked like the clear favorite to lift the Stanley Cup in less than a month.

“It’s not over yet,” Gabriel Landeskog said. “First to four, so lick our wounds, back to work tomorrow.”

No, it’s not over yet, but given the events that took place Sunday night, it sure as heck feels over.

Golden Knights 5, Avalanche 3

What happened: The Avalanche have not been able to put together a 60-minute effort yet this series.

What went right: That first period. That’s about it. Cale Makar returning was great, but he’s clearly not 100%.

What went wrong: Oh boy, where to start? Brock Nelson hit a post, the closest he’s come to scoring this postseason, but that’s not good enough. Martin Necas made a great play on Kadri’s goal, but finished the evening with zero shots at 5-on-5. Wedgewood gave up four goals on 11 shots and couldn’t stop the bleeding.

Avalanche goal scorers: Landeskog (5), Kadri (3), Drury (3)

Golden Knights goal scorers: Stone (4), Karlsson (1), Kolesar (1), Hertl (3), Howden (10)

Between the pipes: Wedgewood stopped just 18 shots.

What’s next: Game 4 will take place Tuesday at 7 p.m.