James DeGale/Photo courtesy of Premier Boxing Champions

James DeGale of England and Badou Jack of Sweden are eight days away from their Jan. 14 super middleweight title-unification bout at Barclays Center in Brooklyn (on Showtime).

It is each man’s biggest fight. Both seem to know what will be the key to victory.

“Oh, there’s loads,” DeGale said of his advantages. “But I’m going to tell you one that stands out is just speed, movement. I’m not going to have to say I’m not going to tell you what I’m going to do because he’s going to be very shocked with what I’m going to do. But speed, I’m so much faster in movement.

“I move my feet so much better – there’s two things right there – that it’s just going to confuse him. I’m going to make things a whole lot harder for him.”

Jack (20-1-2, 12 KOs) is equally confident. To him, it’s about ring smarts.

“I’m the smarter fighter, period,” said Jack, 33. “I believe I’m the more fundamentally sound fighter, I believe I’m the more technical fighter. I take nothing away from DeGale, who is a good fighter as well.

“But I believe in my skills, I believe in myself.”

DeGale, 30, is 23-1 with 14 knockouts.