Shawn Porter revealed the one major difference between Errol Spence Jr. and Terence Crawford.

Spence and Crawford are set to battle next month on July 29 in a welterweight title unification bout that has been many years in the making.

Spence will put his WBC, WBA and IBF titles on the line while Crawford will put his WBO strap on the line to determine a new undisputed king at 147 pounds.

It's a fight that will attract mainstream attention as well, as the duo are two of the best welterweights on the planet with the winner not only being the best welterweight of this generation, but also likely to be high up on the pound-for-pound list.

Porter is one of the few to have faced both.

He lost a competitive decision to Errol Spence in Sept. 2019 to lose his WBC title. He then challenged Crawford for his WBO title in Nov. 2021 and although it was also competitive, he suffered a 10th-round TKO defeat.

It was the only time Porter had been stopped in his professional career as he went on to retire from boxing. And with his experience of fighting both men, he believes there is one decisive difference between the pair.

“Errol was prepared to beat me at my game, and Terence was prepared to beat me at his game,” Porter told Champside (via Boxing Social). “Mentally, there’s a difference. Errol likes to be commander in chief, likes to do what he wants to do. Against me, he chose to try to beat me at my own game.

“Terence – ‘I’m coming in the ring, this is what I’m gonna do, stop me.'”

It's worth nothing that as far as a prediction goes, Porter did make a pick earlier this month — if his life depended on it.

“Somebody text me the other day and I said ‘yeah I feel the same way.’ If I had to bet my life on it, if I had to put money on it, a lot of money on it… I’d put my money on Terence Crawford,” Porter said on his podcast.

Crawford remains a slight betting favorite and seems to be the pick of most big names from the boxing world including another fighter to have faced both men in Kell Brook.

Luckily, fans won't have to wait long to find out.