For 3½ quarters, it was a party, a christening and a public flogging rolled into one.
Then, as quickly as you can say "Joe Pisarcik,'' the world turned, and the Giants made a different kind of history in the biggest game to date in the big, gray bowl.
Yesterday's incredible, inexcusable, nearly impossible 38-31 loss to the Eagles gave the new building a home-team catastrophe to rival anything from the Giants' 34 seasons in its predecessor next door.
(And yes, you could include the Jets' misadventures there, too, but that's another story.)
The Fumble (against the Eagles, naturally) in 1978?
It was a pivotal event in franchise history, but the game itself was not as important as Sunday's de facto NFC East title game.
The playoff loss to the Vikings in 1997?
OK, it was a playoff game, and like Sunday's, it featured a botched onside kick recovery. But those Giants were relatively unimpressive division champs with Danny Kanell at quarterback; these were legit title contenders.
Brian Westbrook's game-winning 84-yard punt return (for the Eagles, naturally) in 2003?
There are obvious parallels, but that Giants team was headed nowhere under Jim Fassel, who ended up essentially firing himself later that season, so the stakes cannot compare.
(I could go on, of course, and I also could mention the 39-38 playoff loss in San Francisco in January 2003, still and forever No. 1 on my personal list of Giants debacles.)
So go ahead and take the rest of the century off, ghosts of Giants Stadium losses past. The new place has a nightmare of its own grim enough to exorcise those demons.
Strangely, the Giants still are in good playoff position, perhaps for a rematch with the Eagles. But the likelihood of a home game and possibility of a playoff bye are all but gone, and despite their three road playoff victories three years ago, that is not the recommended path to the Super Bowl.
Then there is the team's psyche. Can the Giants shake this off in time for a Christmas weekend visit to Green Bay?
"We'll see if we're capable of that; it'll show next Sunday,'' defensive tackle Barry Cofield said. "We will show up like a team that's moved on or we'll show up like a beaten team.''
To their credit, the Giants made no attempt to minimize the shock, with nearly every player admitting, often bluntly, that it was the worst loss he could recall.
Even Tom Coughlin said, "I've never been around anything like this in my life.''
As with any collapse of this magnitude, everything must go wrong, from strategy to execution to luck, including the bad luck to be facing the magnificent weapon that is Michael Vick.
Many mess-ups were both mental and physical, such as Matt Dodge's failure to punt out of bounds on the fateful final play. It happens.
The most aggravating miscue was failing to protect against the Eagles' onside kick after they had drawn within two touchdowns. That was all mental.
Coughlin said the players were warned. But it sure didn't look that way as they peeled back to set up a return while the Eagles easily recovered.
"I don't know what it looked like,'' Coughlin said. "I'm just telling you they were alerted to it.''
Who knows? Maybe the Giants will reach the playoffs, beat the Eagles, turn up in Dallas in February and be able to laugh about all this.
More likely, everyone who wore blue Sunday still will be in no mood to laugh about it until the day the stadium comes down, when they tell the story of a long-ago game that people will find difficult to believe.