When the fight was announced some weeks ago, the reaction of boxing fans was lukewarm.

But with Canelo Alvarez-Amir Khan good to go this weekend, the temperature has shot right up. Khan has bulked up and has spoken a good game from the off. The bookies have noticed, too, and there are not wild odds to be had on him pulling off an upset.

While the fight has percolated, more money has come in on Khan, giving the fight greater appeal. He wasn’t given much chance two months ago, but some sense a ray of light, based on his superior speed.

Forget it. This fight won’t be about the Briton’s speed, especially as it will have somewhat diminished as he’s piled on the kilos. Alvarez’s offence will also see to it.

There are two critical factors in this fight. The first is that no matter how pumped up Khan is, he cannot hurt Alvarez. He doesn’t hit hard enough. The reverse holds true for Alvarez – he can hurt Khan, and badly. Khan knows it too.

The other is that Khan’s chin has let him down in the past and he’s up against a fighter who will have heat-seeking missiles in his fists. Khan has been put over eight times in his career, which points to a sloppiness in concentration and is a perilous weakness. Twice he’s been sparked unconscious, which isn’t a good omen against a man like Alvarez, who can hurt opponents.

The Mexican doesn’t usually start fast and he’s not a one-punch KO artist. But he will pounce on weakness and expose any defensive frailties. Just ask James Kirkland and Alfredo Angulo.

Khan knows exactly what he must do. He’s told us as much, saying he’ll need to box for all 12 rounds, zipping in and out and avoiding any brawling. The minute he tries to engage with Alvarez, fighting on his terms, he’ll be smoked.

Khan can frustrate Alvarez, but it’s difficult seeing him stay out of range for all 12 rounds.

Alvarez is boxing’s biggest star on the post-Mayweather age. I don’t see this changing in a steamy Las Vegas this weekend.

As ever, all the action will be broadcast live on SuperSport 6 from 3am on Sunday.