Either Errol Spence Jr or Shawn Porter will be dealt a sharp dose of reality on Saturday night in a fascinating fight that will take a major stride towards crowning the best fighter in one of boxing’s most interesting divisions.

They call Spence ‘The Truth’ and, so far, everything he has said has come true. He believes he will knock Porter out but has questions to swat away about himself, too.

This is a world welterweight unification bout between two bulls who do not take a backward step, who dig vicious punches to the body, and who make opponents wilt through exhaustion and accumulation.

Spence Jr is the IBF champion (L) and Porter holds the WBC belt Spence Jr is the IBF champion (L) and Porter holds the WBC belt Spence Jr is the IBF champion (L) and Porter holds the WBC belt

Spence Jr is the IBF champion and Porter brings the WBC belt to the table – the winner will own 50 per cent of the welterweight gold, but the fun is only just starting.

Terence Crawford is the WBO champion and indisputably among the top five boxers in the world. Manny Pacquiao won the WBA title from Keith Thurman (who is still a threat to keep an eye on) and has scarcely looked better in doing so, despite now being 40.

And so Saturday night’s fight at Los Angeles’ Staples Center, live on Sky Sports, allows Spence Jr or Porter to shift the paradigm of the division and send out a warning to Crawford and Pacquiao.

“People don’t necessarily understand the level that me and Spence are on,” said Ohio’s Porter.

“We’re both training to knock each other, to go 12 hard rounds, to outclass each other, outbox each other, outpunch each other.

“It’s all about that one moment, and I know I’ve got what it takes to make that moment all mine.

“I’ll take care of Spence then go after Manny Pacquiao, that’s the plan.”

Porter beat Danny Garcia to win the WBC belt Porter beat Danny Garcia to win the WBC belt Porter beat Danny Garcia to win the WBC belt
Spence Jr ended Mikey Garcia's unbeaten run Spence Jr ended Mikey Garcia's unbeaten run Spence Jr ended Mikey Garcia’s unbeaten run

Texas’ Spence said: “It can be a major year for me if I get this knockout. That’s something I will look for, won’t rush into, I will let it come to me, then I will take it.

“I’m looking for the stoppage.

“I want to clear out the division. I want Pacquiao, Thurman, Danny Garcia, Crawford. I want the top guys in the division then, when I’ve achieved that goal, I will move up and conquer another division.”

Spence Jr finds himself in the strange position of being an unbeaten world champion, having just ended the perfect record of Mikey Garcia – one of the elite handful of this era’s boxers – yet attracting criticism for the manner of that result.

Garcia is a brilliant four-weight world champion but, against Spence Jr, he was competing in one division too high. Spence Jr proved bigger and stronger and bullied him, but by going 12 rounds with a much smaller man, has attracted more naysayers than ever before.

Pacquiao climbed into the ring to tease a fight with Spence Jr afterwards, so he should not need reminding of the rewards for Saturday’s fight.

Porter, meanwhile, is an underrated entity – he has lost two world title fights but has stuck around at the sharp end of the division. By beating Danny Garcia (who knocked out Amir Khan) last year, Porter regained a belt and a seat at the top table.

'Last roll of the dice' for Brook-Khan 🎲 @EddieHearn still wants to make @SpecialKBrook v @amirkingkhan and is eyeing a Spring 2020 date for the pairRead more: https://t.co/sis7id89Hu pic.twitter.com/AcTKs7ZtP9

— Sky Sports Boxing (@SkySportsBoxing) September 18, 2019

Spence Jr and Porter have each memorably shared a ring with Kell Brook. Porter was the defending IBF title-holder on the night that Brook ventured to America and became a world champion five years ago.