Saul "Canelo" Alvarez is out to prove he remains the king of middleweight boxing when he puts his titles on the line against Jermell Charlo on Saturday in a clash of undisputed world champions in Las Vegas.

The veteran Mexican superstar heads into Saturday's battle at the T-Mobile Arena with some in boxing wondering whether he is a fading force, after a sequence of recent performances that have fallen short of his normally dazzling standards.

The 33-year-old was comprehensively beaten by Dmitrii Bivol last year when he attempted to step up to light heavyweight in pursuit of the Russian's world title.

He then delivered an underwhelming unanimous decision win in his trilogy fight against an aging Gennady Golovkin, before laboring to a points victory over Britain's John Ryder in May.

Those displays have fuelled belief that Alvarez (59-2-2, 39 knockouts) may well be ripe for the taking against undisputed junior middleweight champion Charlo (35-1-1, 19 knockouts), who is stepping up two weight divisions — from 154 pounds to Alvarez's preferred 168 pounds — in a bid to wrest the Mexican's IBF, WBA, WBC and WBO super middleweight belts.

While Charlo will start as a clear underdog, the skilful 33-year-old from Louisiana nevertheless has the speed and punching ability to cause Alvarez problems.

Los Angeles-based Hall-of-Fame trainer Freddie Roach is one of many neutrals in boxing who believes this weekend could witness an upset.

"I love the attitude Charlo brings into the ring," Roach said. "He cannot be intimidated. He has a great chin and doesn't get fazed by getting hit.

"While both men can fight, I think Charlo will have too much fire power for Canelo to handle."

Alvarez takes that kind of analysis in his stride.

"People will always have something negative to say," he said this week. "I have to prove that I'm still on top."

'I'm a warrior' 

Charlo's recent trash-talking of Alvarez has not gone unnoticed Mexican either.

In video which surfaced earlier this year, the American mocked Alvarez in the wake of his stodgy win over Ryder.

"That bitch can't beat me with that shitty last performance," Charlo said in the video.

Alvarez says he is ready to make Charlo regret those taunts.

"He never believed in my skills," Alvarez said. "He's been calling me out. Now I have the opportunity to show him my skills. And that motivates me.

"I always train 100% and motivate myself, but it's even more for this fight.

"He's called me out for a long time and I'm gonna show him what I can do…he's gonna feel it."

One thing that may work in Alvarez's favor is the relative inactivity of Charlo.

The challenger has not fought in well over a year, since a knockout victory over Brian Carlos Castano in May 2022. If there is any hint of ring-rustiness, Alvarez is more than capable of exploiting it.

Charlo though is adamant that he has the tools to spring a surprise.

"I'm a warrior," he said this week. "I don't think Canelo has faced a fighter of my caliber. He's been in there with great fighters, but there's something I bring to the table that's a lot different than anyone he's seen.

"I defy the science of boxing. What I've been through in life, a lot of people can't compare to that. I'm coming to win this fight, no matter what he says.

"I've backed up everything I've said. Right now this is my time and my moment and I'm gonna proceed and take it."

Legendary trainer Roach tends to agree, believing that the speed of Charlo's left hook could expose Alvarez.

"Canelo needs to stay away from Charlo's left hook," said Roach, who is picking Charlo by stoppage.

"The question is, can Canelo stay away from Charlo's left hook? I don't think he can."