This is one rivalry with sky-high stakes.

The owners of 1 World Trade Center — which will surpass the height of the Empire State Building today — are waging an all-out business war against its Midtown cousin, The Post has learned.

WTC operators want to steal business from the Empire State Building by promoting their observation decks and winning back broadcasters that beam their signals off of the Midtown skyscraper’s massive antenna.

“We’re looking to maximize revenue and maximize the reputation of 1 World Trade Center,” Douglas Durst, who is building the Freedom Tower in partnership with the Port Authority, told The Post.

The antenna business alone could easily rake in $10 million in revenue, estimates show.

And as for the observation deck, the sky’s the limit.

WTC managers say it’s hard to estimate how much revenue the tower could generate because it’s still not decided what amenities will be included in the final design — like gift shops and snack concessions.

But one thing is for sure: the WTC’s observation deck will certainly include much more than just the puny gift shop featured at the Empire State Building, Port Authority sources said.

“You’ve got to get people back to thinking of the trade center not as a site of an attack but as a center of commerce,” said one person who has been involved with the reconstruction of lower Manhattan.

“You’ve got to think about it as a real-estate thing. And real estate is transactional — it’s about competition and retail and tourists.”

The WTC will soon hire an outside firm to design, operate and market its observation deck, which will open with the rest of the structure by early 2015.

And last week, the PA’s board approved a resolution to get back into the antenna business — something that was lost along with nearly 3,000 lives when the Twin Towers fell on 9/11.

The two moves are no coincidence — instead, they should be read as a new aggressiveness on the part of the WTC, sources told The Post.

The PA is even taunting the owners of the Empire State Building.

Tonight, the agency will light the new tower in a blue-and-white color scheme, in celebration of surpassing the Empire State Building’s 1,250 feet.

Those colors, sources said, are supposed to mock the Empire State Building’s controversial 2010 decision not to light the building in honor of the 100th anniversary of Mother Teresa’s birth.

The owners of the 82-year-old Empire State Building declined to comment on their rivals’ plans.

“The world’s most famous office building, the ancestor of all super-tall towers, welcomes our newer, taller cousin to the skyline,” the Empire State operators said. “We’ve watched you grow, and now we salute you.”