The pair went head-to-head for the undisputed welterweight title last month and it was Crawford who emerged victorious in Las Vegas. 

But what surprised many fans was how dominant Crawford was in this particular matchup with the Omaha fighter managing to knock down Spence on three occasions, once in round two and then twice in round seven. 

The fight was eventually stopped in the ninth and after being crowned the undisputed champion in a second weight class, Crawford has a valid case as to why he should be considered the world's number one pound-for-pound fighter. 

Reflecting on the fight ahead of Emmanuel Navarrete's WBO super featherweight title defence against Oscar Valdez, Arum explained why this particular weakness when it comes to southpaw fighters resulted in total domination from Crawford. 

"Look at Spence’s body of work, and what clue do you see there which would lead Crawford to victory? And the clue that I saw was that out of his fights — I think he had 28 fights — of all those fights he only fought two southpaws," Arum told Fight Hub TV. 

“So what does is that telling you? It’s telling you that he has trouble with southpaws because to only have two out of (28) fights, it means that his people, or himself, have looked to avoid southpaws.

“Now Terence’s big strength is that he fights equally well from either side. So instead of opening up as a right hander as he usually does and switching to southpaw, he only fought Spence as a southpaw and Spence couldn’t handle it, particularly when Crawford who is ambidextrous and now his right hand jab is throwing it with force and hurting Spence.

“So once I saw Terence come out as a southpaw, in my mind I thought ‘hey, the fight is over.’”