The winner of the Errol Spence Jr. vs. Terence Crawford fight will determine the pound-for-pound best boxer in the world.

That's according to Crawford who currently holds the top spot in many a pound-for-pound list. However, his spot could be under threat following Naoya Inoue's win over Stephen Fulton on Wednesday morning.

Inoue became a four-division champion after knocking out arguably the best junior featherweight in the world to win the WBC and WBO titles.

For many, the undefeated Japanese superstar is already the pound-for-pound best boxer in the world. But as far as Crawford is concerned, his fight will determine who gets the top spot and there's a very simple reason for that.

His opponent in Spence.

“100%,” Crawford replied in an interview with SI when asked if the winner of his fight will be the pound-for-pound No. 1. “Everybody in the world knows that the winner of this fight is the number-one pound-for-pound fighter in the world, undisputed. There’s no comparison.

“Not to take anything away from Inoue. He’s a talented fighter. He’s great at what he does and he looked spectacular in his recent fight. But everybody in the world knows this is a fight where you got the number-one pound-for-pound fighter [Crawford] fighting the number-four pound-for-pound fighter in the world [Spence].

“No disrespect to Stephen Fulton, but he wasn’t nowhere near the pound-for-pound list. So that tells you something right there.”

Terence Crawford certainly has a point. Fulton was definitely not in many people's pound-for-pound list whereas many have Spence in the top five at the very least.

Whether a Crawford win over Spence is enough to diminish Inoue's claim remains to be seen, however.