It's early into the year, and we already know that the Cadillac Escalade is the most popular full-size luxury SUV in the U.S. It's bested Infiniti QX80 and the Mercedes-Benz GLS so far, and sales are up eight percent. But now the Lincoln Navigator is rising up, and Cadillac is scared enough to start offering incentives.

To dissuade people from getting a new Navigator, Cadillac is offering a $10,000 discount toward the lease of a new Escalade. To keep current leasers from swapping their SUV out, they're also offering a $7,500 discount to existing owners.

Jeff Schuster, an analyst at LMC Automotive, spoke about the new incentive.

“GM is trying to keep Escalade buyers out of Navigators, for sure. You’ve got a fresh Navigator and you’ve got an Escalade that is not new and is starting to age. GM is willing to forgo a little profit to keep loyalty within the brand, but they’re still making money. The new Navigator has sent a signal to Cadillac that they need to be in front of this and be aggressive.”

Lincoln still has a while to go before it overtakes the Escalade. Their first-quarter sales were only about half of what Cadillac had, nor are they even number two on the market. The competition's fear is due to the Navigator's 63 percent rise in March. Most models are sold off the lot in only 10 days. They're moving fast.

The Navigator is newer, as well. It went on sale last year, while the most recent Escalade is about four years old now. When it comes to vehicles, even a year can make a difference.

Are these incentives enough to keep pulling in the numbers Cadillac wants, or will they fall wayside to the Navigator? Only time will tell.