This is what this place can be: every seat filled, every voicebox sore, every nerve frayed, every pitch a referendum. At its very best, this was always what Shea Stadium was: maybe not the loudest building in town (that was always the Garden), maybe not the most intimidating (that was the big ballyard in The Bronx).

But a little bit of both. The very best of both.

“This,” David Wright said, “is the way it’s supposed to be.”

The Mets beat the Yankees on Friday night, 5-1, beat them in an old-time Yankees way with three home runs, beat them even as the Yankees tried to shake down a few old goblins in the ninth inning, loading the bases with only one out, giving the several thousand Yankees fans among the 43,602 a narrow boulevard of hope.

And when it ended, when Jeurys Familia threw strike three past Chase Headley, there was a wonderful spasm of energy, a jolt that seemed to shake the new park ever so slightly. And for the briefest moment, the new joint felt an awful lot like the old one used to.

“When this place gets loud,” manger Terry Collins said, “you know about it. The players talk about it.”

In many ways, this was Opening Night at Citi Field, the very first time when there was a confluence of big game, heated opponent, sellout crowd and stakes on the table for both teams involved. Both the Mets and Yankees had divided attention spans, the Mets peering at the Nationals-Marlins score (Nats win) from Washington, the Yankees peeking at Blue Jays-Red Sox from Toronto (advantage, Jays).

And, of course, they had their attention glued to each other, too. For most of the night, it was just chilly enough to remind you it was September (with October swinging a weighted bat on-deck) and the pitchers, Masahiro Tanaka and Steven Matz, were brilliantly matched in a game of wills.

The baseball was terrific, a 1-1 game in the sixth when the managers started to play chess. Two on, two outs, and there had to be a temptation for Terry Collins to walk the Yankees’ 8-hole hitter, Brendan Ryan, and force Joe Girardi to either let Tanaka bat and kill the inning, or take him out despite an absurdly low pitch count.

Collins, smiling: “I’m not letting Alex Rodriguez come into the game to face Steven Matz.”

Girardi, confirming: “I probably would have had Al pinch-hit there.”

Ryan grounded out on the first pitch he saw, Daniel Murphy slammed a two-out home run in the bottom of the inning, and what had been a tense, tight match-up turned instantly joyous for the home team and the home fans. Juan Uribe added a two-run blast in the seventh. A fifth run scored on a wild pitch in the eighth.

“A total team effort,” Collins said.

That extended to the grandstand, to the Pepsi Porch, to the Party City Deck and the Promenade, everywhere Mets fans had come to experience the first big, big, BIG game in the history of Citi Field, to see how it stood up to the ghost of the old dump that used to stand, hulking and harrowing, next door.

Old Shea had its flaws and its detractors, but there was no denying the impact it had as a home-field advantage, whether you were cheering on the Mets, the Jets or the Beatles. The place shook, sometimes violently, sometimes to the point at which you wondered how the architects could leave it so vulnerable to a Joe Namath touchdown pass to Don Maynard, to Endy Chavez bringing a home run back over the wall, to Lennon and McCartney harmonizing on “Help!”

The foundation didn’t rattle Friday night. But it wasn’t as if the people didn’t try. A lot of our new buildings haven’t measured up. There isn’t a Giants or a Jets fan who ever has said a kind word about MetLife Stadium with its antiseptic look and anti-fun vibe — certainly not as it compares to old Giants Stadium.

Yankees fans tried to turn the new palace in The Bronx into the old version of itself during the playoff run in 2009, but there’s just too much wide open space now, too many places for the din to die. And even if Madison Square Garden’s walls remain the same, the atmosphere inside has changed dramatically since the billion-dollar facelift.

“Maybe,” Collins had said before the game, “these three games can lead to something nice in the next 10 days.”

Maybe. So far, the new place is off to a flying, fabulous start.