Fire Nick Sirianni and all his coaches after this Eagles humiliation against the Giants? OK.

EAST RUTHERFORD, N.J. — Fire everybody.

Well, everybody except Big Dom. At least he showed some fight this season.

Nick Sirianni’s overpaid underperformers entered MetLife Stadium on Sunday to face a hopeless team playing for nothing but draft picks and pride. The Giants fell a few draft slots but won the game, 27-10, over an unmotivated, unprepared, unfocused flock of Birds, and laid things bare:

This Eagles coaching staff is overmatched. By everybody.

Sirianni won’t get fired — he’s made the playoffs in his first three seasons as a head coach and nearly won the Super Bowl last year — but nobody on his staff can be considered safe, outside of legendary offensive line coach Jeff Stoutland. I dunno. Maybe just clean house and keep Stout.

Jeffrey Lurie has to be considering it. A former NFL executive told me three weeks ago the Eagles were a “clown show,” and Sirianni is its preening, taunting ringmaster.

Lurie must have been humiliated Sunday. He left his suite in the press box with a strange smile on his face, but looked grimmer when he entered the locker room. Maybe he already has his mind made up. His team is so badly coached that it lost to both Tommy “Cutlets” DeVito and Tyrod “Cube Steak” Taylor, anonymous quarterbacks who took turns embarrassing the Birds on Sunday. If you thought barely losing at home to Arizona last week was rock bottom, all you had to do was wait a week.

The Eagles trailed, 24-0, at halftime. They’d committed two turnovers, given up three straight touchdowns, and had their backups in the game before the end of the second quarter.

The Birds barely beat these Giants in Philadelphia two weeks ago. Apparently, the Giants took notes. They knew every play call, every defensive weakness, every tendency, and every crack. They exploited all of it.

Just like former defensive coordinator Jonathan Gannon and his four-win Cards had done a week before, the six-win Giants befuddled the Birds. These teams were not the first to do so.

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The Eagles are chronically badly coached. Unimaginative. Predictable. Stubborn.

They are coached like a high school team that believes that no matter how simplistic its schemes, no matter how vanilla the play calls, their blue-chip recruits are gonna get them to the state playoffs.

Except this is the NFL, and even the worst teams have blue-chippers, so the best teams need an occasional dash of genius to engineer wins. The Eagles coaches have shown all the genius of Beavis and Butt-Head.

The Eagles had a chance to win the NFC East, but they played like a team content to take their No. 5 seed and get out of the cold weather. Considering the stakes, the talent level, and the opponent, this was the worst Eagles loss since Lurie bought the team in 1994.

The Birds were 10-1 after beating the Bills in overtime on Nov. 26, the best record in football. They lost five of their next six games. They fell from the first seed to the fifth and lost the NFC East to Dallas. Now they’ll fly to Tampa, where, inevitably, they will lose their sixth of seven games, thereby mercifully ending this two-month nightmare.

“You have to flush this last month,” Sirianni said. Hmmm. In their last six games they’ve been outscored 182-123. Not sure that one’s gonna make it down the toilet, Nick.

They would have little chance to win at Tampa even if they were fully healthy. They have no chance now, because they fell like flies on Sunday.

Pro Bowl wideout A.J. Brown injured his right knee in the first quarter. Safeties Reed Blankenship (groin) and Sydney Jones (knee) and right guard Cam Jurgens (eye) also left and did not return. Jalen Hurts injured his right middle finger in the second quarter, stayed in the game, threw an interception, then left when backups entered.

Whatever happens in Florida, it cannot be worse than the catastrophe that occurred in the first 28 minutes here Sunday. That’s because the Bucs, at least, are a playoff team.

This is the latest in a growing stretch of Philly failures. The Sixers blew a 3-2 series lead over the Celtics in the Eastern Conference semifinals. The Phillies blew a 3-2 series over the Diamondbacks in the NLCS. Now, this.

This is worse. This is the worst thing that’s happened to Philly in 60 years.

In 1964, the Phillies held a 6½-game lead with 12 games to play. They lost 10 straight, and, with it, the pennant. This is the worst collapse since then, except that scenario played out over a week-and-a-half. That’s momentum.

The Eagles went from first to worst over almost two months. That’s coaching.

They stink, because they play sloppily. Sirianni is in charge.

They stink, because they call bad plays. That’s first-year offensive coordinator Brian Johnson’s department.

They stink, because they don’t use their defensive talent properly. That cost first-year coordinator Sean Desai play-calling duties four games ago. “Senior defensive assistant” Matt Patricia took over. Things got worse.

Everything is worse.

» READ MORE: Eagles grades: Disaster strikes again as several phases struggle and earn F marks in Giants loss

Name something, anything — any of those four coaches has done in the past two months to preserve their employment. Name one area on the team that got better.

Hurts, the $255 million quarterback, got much worse. He was the MVP favorite at the end of November. By Sunday evening, he’d become Ryan Tannehill Lite.

Young defensive tackles Jordan Davis and Jalen Carter got much worse. Oldster Fletcher Cox had gotten so bad that Sirianni gave him the day off Sunday. Davis and Carter? They just didn’t show up.

After the first eight games, A.J. Brown was on pace to log one of the best seasons in history for a wide receiver. Teams adjusted, the Eagles coaches didn’t, and Brown turned into Nelson Agholor.

Don’t blame the injuries for the debacle Sunday.

Brown fumbled milliseconds before Nick McCloud landed on his leg.

Hurts took two awful sacks because he didn’t recognize blitzes, and that had nothing to do with the finger. He finished with a passer rating of 26.8, third-worst of his career. The defense was plenty healthy when it gave up 10 first downs during those three TD drives.

Sirianni didn’t dress Pro Bowl running back D’Andre Swift, who was ill, or receiver DeVonta Smith, who injured an ankle on a bad play call at the end of last week’s loss, or cornerback Darius Slay, who had knee surgery last month. Cox, you recall, got the day off.

So did security chief “Big Dom” DiSandro. He’s serving a suspension from the sideline after a tussle with 49ers linebacker Dre Greenlaw on Dec. 3.

Unlike the football players and coaches, Big Dom will always be beloved in Philly, because the last time Philly saw Big Dom, he was putting up a fight ... unlike the football players and coaches.