Floyd Mayweather’s height will be a huge advantage in the fight. Source: Getty Images

He will do so because he has a greater capacity to set distance between himself and his opponent, and capitalise with his jab without getting caught.

And he will do so because Pacquiao won’t be able to get set to land the killer blow he needs to win this fight. Pacquaio hasn’t been able to stop an opponent in more than five years — and those he has fought in that time have lesser defensive skills than Mayweather.

The undefeated Mayweather won’t go chasing Pacquiao, saying: “Manny Pacquiao fights better going backwards, he is a fighter that likes to move backwards and fight, he can’t fight as good going forward.”

MAYWEATHER-PACQUIAO ULTIMATE FORM GUIDE

GREEN: PAC MAN MUST BE PERFECTLY WILD

WHY FLOYD IS SMART THAN HE LOOKS

Boxing: Manny Pacquiao says he is feeling relaxed and ready ahead of his big fight against Floyd Mayweather

The taller Mayweather will position his lead left foot just in front of Pacquaio’s lead right, establish his jab into Pacquaio’s face and body using his five inch reach advantage, spring backwards as Pacquaio tries to retaliate and catch him with lightning fast counterpunches.

Pacquiao’s only hope of an unlikely victory is to hurt Mayweather early, rock him from his comfort zone and finish him.

That is the longest of long shots, despite the inevitable boxing hype surrounding a big fight shortening the odds of the underdog and instilling false belief in supporters.

Pacquiao’s legend lives off the devastating knockout win over Ricky Hatton, and his beat down of Oscar De La Hoya. Those victories were in 2009 and 2008 respectively.

The calm before the storm ... Mayweather and Pacquiao are all smiles at the press conference. Source: Getty Images

His last stoppage win, against Miguel Cotto, was also in 2009, Pacquiao’s crowning year. Since then he has fought nine times without being able to knock out an opponent, easily the longest stretch of his career without a stoppage.

That doesn’t mean Pacquiao has lost his power, it means that Pacquiao has been unable to set himself to throw the defining punch that starts from his toes, flows through his enormous calves, up into his left quad and hips, sears through his left arm and glove and onto the chin of a hapless rival. The one that knocked Hatton cold.

And that means opponents have figured out how to avoid Pacquiao’s best shots.

In this stretch of nine fights, Pacquaio has also been knocked unconscious himself, by Juan Manuel Marquez in 2012, with a counterpunch.

Boxing: Floyd Mayweather previews his big fight against Manny Pacquiao.

Mayweather is the best counter-puncher in the business.

He will defeat Pacquiao in Las Vegas because two of the judges for the fight, Dave Morretti and Bert Clements, are so familiar with Mayweather’s tactics and style, they will appreciate the American’s reluctance to engage in a slugfest with Pacquiao, and will see Pacquiao’s numerous blows glancing off Mayweather’s gloves or left shoulder.

Morreti has judged seven of Mayweather’s past nine fights, and has always given him a wide winning margin; eight rounds to four against Marcos Maidana (twice) and Saul Alvarez, nine rounds to three versus Cotto, 11 rounds to one versus both Marquez and Shane Mosley, and eight rounds to one versus Hatton before Mayweather knocked him out in the 10th.

Clements was a judge alongside Morreti when Mayweather fought Maidana the first time, Marquez and Hatton, and was even more impressed, giving him nine rounds versus Maidana, all 12 rounds versus Marquez, and the same eight to one against Hatton before the stoppage.

Neither judge has scored a Pacquaio fight since 2011, when Moretti gave Pacquaio seven rounds to five over Marquez in a majority decision win for the Filipino.

Boxing: Paul Upham previews Floyd Mayweather v Manny Pacquiao

The last time Clements scored a Pacquaio fight was in 2004 — the first fight against Marquez, which he judged a draw.

Pacquiao will throw far more punches, but Mayweather will throw more accurately. Morretti and Clements will give Mayweather the rub of the green in close rounds.

Much has been made about Mayweather’s apparent struggles with southpaws — left-handed fighters who lead with the right jab, as Pacquaio does.

But Mayweather has so far defeated eight southpaws and successfully used switch hitting — where he changes his own stance from right to left — to nullify punches coming from awkward angles.

A Pacquiao victory would be a wonderful fairytale, a triumph for aggression and excitement, but it doesn’t quite concur with boxing logic.