Christmas came early this year — for scalpers and fans with tickets to sell for Saturday’s big showdown between the Giants and Jets at MetLife Stadium.

The do-or-die game is a rare, regular-season meeting between the local rivals that share the stadium — and the stakes for both teams are so high that the matchup is sending ticket prices soaring into the stratosphere.

The average price yesterday on the secondary market was a whopping $384.25 a seat — 22 percent higher than it was on Dec. 1, said Chris Matcovich, of TiqIQ, a ticket-price tracker

“It’s basically a playoff game for both teams,’’ Matcovich said, noting either Gang Green or Big Blue could be bounced from Super Bowl contention with a loss.

The Showdown at the Swamp, which is technically a Jets home game, is currently the second-highest-priced contest for secondary-market NFL tickets at the Meadowlands stadium since it opened last season.

Only the Giants’ New Year’s Day season finale against the Cowboys, which is currently commanding an average $462.60 a ticket, is higher.

But brokers warn that price could fall to around $300 if the Giants are knocked out of playoff contention before the Jan. 1 kickoff.

The average face value of tickets to Jets games is $120.85, while Giants tickets average $111.69.

Jets and Giants fans yesterday vowed they’d be at the Christmas Eve game no matter the cost.

“I’m getting to this game one way or another — even if I have to pay $250 to $350 a ticket,” said Kevin Daunt, a Staten Island longshoreman and former Jets season-ticket holder.

“Part of me wants to grab them now, but I’ll wait until the last minute and hope the prices drop, so I can get great tickets.”

Daunt will be vacationing with his family in the Poconos for the holidays but said he “got the blessing” from his wife to sneak off for a few hours for the game with his son, Robert, 20, and daughter, Kristen, 18.

“[Yesterday] was my daughter’s birthday, and she wants to go as a present, so I have the perfect excuse,” joked Daunt.

Longtime Giants fan Robert Bivio of Brooklyn is trying to find a friend with Jets season tickets to take him to the game — but if that fails, he’s willing to pay up to $400 for a seat.

“I would love to see the Giants shut up [loudmouth Jets coach] Rex Ryan,’’ Bivio said.

“Can’t wait!”

Game on

Secondary-market pricing for the Jets-Giants Christmas Eve face-off:

* Average ticket price: $384.25, up 22% since Dec. 1 and 5% since Sunday

* The 3,800 available tickets range in price from $173 to $6,000.

* Season-average prices for Jets and Giants tickets: $219.68 and $304.75, respectively

Source: TiqIQ