Hall of Fame trainer Ignacio "Nacho" Beristain sees no way that Shawn Porter can shock Errol Spence when they collide for the WBC, IBF world titles on Saturday night at the Staples Center in Los Angeles, but he also ruled out, from his assessment, that Spence could be the best welterweight in the world.

He believes the best welterweight out there is WBO world champion Terence Crawford.

Beristain is pleased that this unification bout is taking place, because these types of fights are the kind that the public enjoys. But above everything he stressed that if Spence and Crawford get the chance to face each other, it would undoubtedly be the fight that could paralyze the boxing world.

"Spence to me is a great fighter. I would stay on the side of Spence in this fight. I've been impressed with him since the moment he fought with a fighter of mine, Alejandro Barrera... in fact he broke his jaw in the second or third round, he is a good fighter," Beristain said to ESPN Deportes.

"Porter I don't know much about him. I know he is going to make the fight difficult, he has a style that is complicated for some and he is competitive, but Spence's technique is going to be imposed. For me Spence is one of the best welterweight in the world. I think he can beat Porter, but I don't think he can do the same with Terence Crawford.

When asked about Spence and Crawford, he said Terence's technique is better.

"Spence looks good, or has looked good, but the other one is technically superior, his liver hooks are deadly... without a doubt Crawford is a lot more in my view. What would be good is for them to fight, even if it's difficult to get it done I wish they did," explained Beristain.