The fans inside United Center were the very last to know. They were on their feet (most up off their feet, really) hollering and high-fiving in their Kane and Chelios and novelty Griswold jerseys, finally releasing all the tension that had gripped them throughout Wednesday’s Game 7 between the Chicago Blackhawks and the Detroit Red Wings. Chicago’s Niklas Hjalmarsson had just scored to break a 1-1 tie with 1:49 to play, and now “Chelsea Dagger” was DA-da-da-DA-da-da-DA-da-da-DA-ing over the PA system, and life was pretty great.

Viewers watching at home found out almost immediately that the goal was being disallowed. In the press box, partially deafened by the goal horns, we struggled to make sense of the little things that didn’t seem quite right — the refs were huddling, Chicago captain Jonathan Toews seemed angrier than usual, and no one was skating toward center ice. But most of the fans were too busy celebrating to really notice — like some scene from a dark comedy in which a happy, waving, unsuspecting dude doesn’t realize he’s about to get taken out by a bus. (Actually, that dude could be Hjalmarsson himself: “I was probably looking like a fool celebrating in the middle of the ice,” he later said.)

Then “Chelsea Dagger” was abruptly cut off, mid-da-DA; the only thing missing was a record scratch. Referee Stephen Walkom had blown the whistle before the shot to assess coincidental minors on a scrum developing in the neutral zone near the benches, and the winning goal was null. Little red rally towels began littering the ice. A “bullllll-shit” chant spread through the arena, though it lacked the fervor and abandon of the celebration that had taken place just moments before. In an instant, everything had changed, and everyone was newly furious and nervous all at once.

It was a strange call from a man who used to be the director of NHL officiating, and who has a reputation among many NHLers for “just lettin‘ ’em play.” (Last season, he called nothing on a Raffi Torres hit that concussed Marian Hossa and led to Torres’s suspension.) It’s possible Walkom was being extra vigilant because of an earlier incident in the same spot that left the Red Wings’ Valtteri Filppula hobbling around on crutches. Some speculated he didn’t want to cause a power play at that point in the game, and instead copped out by issuing matching roughing penalties to Kyle Quincey, who deserved one, and Brandon Saad, who didn’t really seem to.

Of course, in the playoffs it’s hard to ever know what constitutes a penalty.

“These games are highly contested and real hard to officiate,” Red Wings coach Mike Babcock said after the game. “If this was a regular-season game, there would have been a parade to the penalty box with what goes on out there. That’s why the playoffs are so much fun — because they’re hard.”

Watching the replay, Walkom made the call before the shot was taken; it’s not like he could have known that Hjalmarsson was going to score what was for one brief shining moment the biggest goal of his career. Still, the whole thing was a disaster. Toews would later describe the Chicago bench as experiencing “violent emotion” — to say nothing of how the fans were holding up. I grew slightly worried about what might happen if the Red Wings were to score in the dying seconds of regulation.

No one did, though, despite several scoring chances, and the intermission leading into overtime felt long and full of dread. Either way, one team was going to go home with a brutal loss. For Chicago, it would be cruel whiplash (not to mention an unacceptable finish for the top regular-season team); for Detroit, it would mean they’d blown a 3-1 series lead. Mercifully, the sudden-death period didn’t last for long. About three and a half minutes in, Chicago’s Brent Seabrook fired a snap shot from 32 feet out that grazed off Wings defenseman Niklas Kronwall and evaded talented young Detroit goalie Jimmy Howard. This time there were no whistles on the play: 2-1, Chicago. The Red Wings on the ice hunched over, hands-on-thighs; the ones sitting on the bench slumped face-in-hands. The Blackhawks looked like this (and I imagine Walkom’s friends and family did as well):

“It was a pretty exhausting game,” said Seabrook, “but I was more tired during the celebration, from all the guys jumping and punching me in the face and dragging me down and pulling my head down.”

In the desolate and devastated Red Wings locker room following the game, Kronwall spoke so softly it was hard to hear him. Behind him was a door to the trainer’s room; every time it swung open you could catch a quick glimpse of Pavel Datsyuk sitting on a table and staring off into the distance.

“Right now it’s just empty,” Kronwall said.

“Of course it feels really empty right now,” said Wings captain Henrik Zetterberg, whose goal had tied the game 26 seconds into the third period. (Also, his third-intermission snub of Pierre McGuire became an instant classic.)

Next door, the Blackhawks clubhouse was packed, with constellations of camera crews and reporters half-circling nearly every player. One of them was Patrick Sharp, who put the Blackhawks on the board early in the second period when he started and then finished off a remarkable series of passes for his seventh goal of the playoffs.

“When we’re out there on the ice competing, playing hockey, it’s what we’ve done our whole lives,” Sharp explained. “It’s probably tough for the fans and for the people watching to go up and down with the emotions but for us it’s just a hockey game … and we’ve dealt with that kind of stuff for a long time.”

Seabrook also referred to a lifetime spent playing hockey. “Shooting pucks around in the front yard, against the garage, breaking garage doors, it’s always something you think about: scoring an overtime winner, Game 7,” Seabrook said.

The Blackhawks advance to play the L.A. Kings in the Western Conference finals in back-to-back games on Saturday and Sunday. (Rolling Stones concerts on Friday and Monday hemmed the schedulers in; you can’t always get what you want.) The Red Wings, meanwhile, will now have time to reflect on their season, from the many positives — they overcame a number of significant injuries; they battled their way into the playoffs on the last day of the regular season; they came back from a 3-2 first-round series deficit against the no. 2 seed in the West to advance in seven games; they very nearly beat the league’s top team — to the disappointing and sudden way things ended.

“Those dreams you have as a kid in Game 7, you always score,” Babcock said. “The other team doesn’t score.”