When on Saturday Saul “Canelo” Alvarez walks to the ring to defend his undisputed super-middleweight title against Jaime Munguia, there will be one spectator among the crowd at Las Vegas’ T-Mobile Arena watching with a particularly keen eye.

The all-Mexican confrontation, on the occasion of Cinco de Mayo weekend, comes with Alvarez under increasing pressure to fight David Benavidez, the American widely considered to represent his greatest threat.

It also comes two years after the defeat by Dmitrii Bivol that triggered suggestions that the world’s highest-profile fighter is in decline, which in turn preceded three successive victories in which he struggled to demonstrate the explosive qualities that often defined his admirable ascent when, on each occasion – against Gennady Golovkin, John Ryder and Jermell Charlo – he was as much a favourite as he is against Munguia.

That Munguia represents his first Mexican opponent since Julio Cesar Chavez Jr in 2017 will resonate with Robert Diaz – the respected matchmaker once of Golden Boy Promotions – more than most. Diaz’s career owes much to his association with Marco Antonio Barrera, whose trilogy with Erik Morales made theirs the most revered rivalry in the history of Mexican boxing. Diaz also became aware of Alvarez before he agreed promotional terms with Golden Boy, and therefore worked alongside him while Golden Boy guided him into the position as the successor to Floyd Mayweather as the richest and most popular fighter in the world.

“I remember being in Phoenix, Arizona for an event,” Diaz recalled. “Coincidentally, Eddy and ‘Chepo’ [Reynoso] were there. He gives me a DVD, and says, ‘Take a look at this kid – what do you think?’ ‘Canelo’ was probably if not 14, then 15 years old.

“Not only was he different because of the look – being Mexican, but a red head. But he boxed different, and obviously we see today that he’s not the typical Mexican fighter. He boxed different because it was a Mexican-American style. It was a boxer counter-puncher – which eventually that’s what he ended up being.

“Three years [later] as he grew, and started building a career in Mexico, I moved on and started working for Golden Boy, and Eric [Gomez, who remains Golden Boy’s matchmaker] was very close to Chepo and Eddy, and they worked out the deal to sign him. Yes, at the beginning, there was a little excitement to work with this young kid who had already a tremendous record, but you didn’t know or expect how big, or where it was gonna go. Yeah, there was some talent, but as much as he believed he was gonna be one of the best and a great superstar, you didn’t see it yet. It was still early stages.

“Little by little you started seeing things different; how he gets better and better in every fight. I’ll tell you, personally, what was great to work with him and how I was excited, is there really wasn’t a stress or a struggle to match him. To this day he basically wants to fight everybody – and has fought everybody – and there was times where you don’t want to fight this guy. ‘Hold on, not him’, and he would say, ‘That’s who I wanna fight’. 

“Austin Trout was one I didn’t wanna go into; Erislandy Lara was another one. Those were the two main ones where I remember saying, ‘Wait, why don’t we think of someone else?’, and I remember him saying, ‘No, that’s who I want’. So he was always like a dream to work with in that sense that made it very easy.

“In any fighter’s career it’s all about timing. I’d love to take the credit as a matchmaker for him, but I wouldn’t be honest to myself. Matching him – basically he would come and say, ‘Look – I wanna fight this guy; I wanna fight that guy’. Even when he fought [in 2019, Sergey] Kovalev, I was like, ‘Wait a minute – we’re going way too far’. A few years before Kovalev was very dangerous; very dangerous; no one wanted to fight him. It’s all timing, and it’s all when a fighter really wants to go for legacy and challenge himself. 

“It’s sometimes very difficult – especially like a fighter like Canelo, who’s done it so many times. To really get up for a training camp – eight, 10 weeks; whatever the camp is – you gotta be motivated. Especially Canelo – I say it again, because you’ve already reached the pinnacle; you’ve already reached the top; you’ve made so much money; you’ve won so many titles. It gets to a point where it’s not about money; it’s not about titles. It’s legacy, and you need that right dance partner to get up in the morning to motivate you to run; to put in those rounds of sparring. 

“Either you love it, or you’re looking for something that just really bumps you and motivates you. In Canelo’s case it really is that. He loves what he’s doing; he loves boxing. But I really believe you’ve gotta be motivated, and he’s looking for those challenges.”

Before his departure from Golden Boy at the start of 2023 – which concluded 15 largely successful years – Diaz had attempted to sign Bivol having recognised the Russian’s considerable potential, and he was present in Vegas when Bivol inflicted Alvarez’s second defeat. For all that Alvarez, 33, expressed his desire for a rematch, it is Benavidez, and not the 27-year-old Munguia, he is under pressure to fight – as he once was with Golovkin.

“With Golovkin, I feel deep down inside he always knew he could beat him, because when he first encountered him it was in Big Bear [California], sparring,” Diaz said. “Canelo had just arrived in Big Bear; the altitude change; Golovkin basically lived in high altitude; was already in camp training. 

“They sparred two times – and Canelo never told me this. A friend of mine – a coach that was there with another fighter – told me, ‘Man, I just witnessed amazing sparring’. ‘Who?’ ‘Canelo against Golovkin.’ ‘No, it’s not Canelo – you confused him’. Canelo still wasn’t as known. ‘You confused him – the guy that’s up there is Craig McEwan.’ 

‘No, no, no – I’m pretty sure it’s the Mexican kid, Canelo, and he bloodied Golovkin up.’ I made some calls, and sure enough it was Canelo. 

“It was impressive, because he was still very young, and Golovkin was already established. If I’m not mistaken Canelo was probably still a welterweight; Golovkin was already the middleweight. It was a matter of filling into the weight properly. Not just jumping up in weight, but maturing, and it was a matter of time before that got done and we saw it.”

It’s since the defeat by Mayweather in 2013 that Diaz’s wife Karla has worked as Alvarez’s personal assistant, contributing to Diaz – on Wednesday Alvarez clashed with his former promoter Oscar De La Hoya – retaining the positive relationship with him that is shared by so few at Golden Boy.

“It’s easy to see Alvarez as a superstar for all the achievements he’s done in boxing, but as everybody knows him as ‘Canelo’, we know him as ‘Saul’, and the Saul that we know is outside of the cameras; outside of the ring,” said Diaz, who continues to work with Sheer Sports Management. “He’s been very much the same person. 

“Early on he was very mature. Early on he was somebody that his group – his circle – was small. Of course it’s grown at this point, but it’s because his companies have grown. He has a lot of businesses outside of boxing. With that, the circle gets bigger outside of boxing. My wife’s very happy working for him, and he treats her where she’s happy. They’re good for each other and it’s benefitted both sides and I see it being for many more years to come.”