Saul 'Canelo' Alvarez has dismissed suggestions he only agreed to fight Gennady Golovkin after the Kazakh struggled to victory over Daniel Jacobs in March.

The Mexican, 27, finally faces WBC, IBO, WBA and IBF middleweight champion Golovkin on Saturday at Las Vegas' T-Mobile Arena in the most significant fight since Floyd Mayweather defeated Manny Pacquiao in 2015.

Golovkin, 35, went the 12-round distance for the first time in a lethargic defeat of Jacobs which some observers felt the American had won.

Alvarez's promoter Oscar De La Hoya has also spoken of the fact Saturday's fight took 18 months to negotiate, and at a time when Golovkin appeared the hungrier of the two fighters. The Mexican, however, insists that that is merely incidental, and denied that the agreement was only reached when the undefeated Golovkin showed signs of decline.

He is adamant that it was already in place before that unanimous decision, even though De La Hoya had long appeared to be allowing time for him to develop, and also does not agree that in that period he has become the physically bigger man.

"We basically had a deal done before the (Jacobs) fight," said Alvarez, who in May defeated Julio Cesar Chavez Jnr at super-middleweight.

"He just had to be victorious and I had to win my fight, so no, it had nothing to do with it.

"This is the fight we'd always wanted and it was going to happen for September.

"I still think (Golovkin) fights at a very high level.

"He's actually a little bit bigger, but it doesn't mean that he's stronger than me. If you look at his knock-outs and my knock-outs, mine are a little better than his. It's not just about the power; it's about precision, and I've attained that."

The widespread belief that Saturday's match-up, which will be supported further down the bill by Britain's Nicola Adams against Hungary's Alexandra Vlajk, will prove as exciting as it will competitive has already led to talk of a potential trilogy.

Golovkin has long been considered one of the greatest middleweights in history but one in need of victory in a defining fight like this to truly prove that, but Alvarez is adamant he will win so convincingly that they will never fight again.

"I'm going to prove in the first fight that there's no reason for a second and third one," he said.

"Of course he's one of the best (of all time). He's demonstrated it: he's very strong, and I know it's going to be a difficult fight. I'm confident I'm going to win, but it doesn't mean it's not going to be a difficult fight."