Eddie Hearn is Devin Haney’s promoter and talks to BBC Sport about the American’s WBC lightweight title defence against JoJo Diaz this Saturday in Las Vegas – as well as how the division is looking after Teofimo Lopez’s shock defeat by George Kambosos.

This week, our own Devin Haney takes on the toughest test of his career against two-weight world champion JoJo Diaz. Haney wants to cement a mega-fight in the 135lbs division, but let’s be honest, is anybody safe right now?

So often in boxing, you focus on the next fight. It could be an undisputed contest, it could be a super-fight in the division – but then a fight that looks like a relatively straightforward job turns into a nightmare. That’s what unfolded for Lopez against Kambosos. The idea of the four kings of the division evaporated. Kambosos, having dethroned Lopez, was even calling himself ‘the Emperor’ of the division afterwards.

I do think it was tight for Lopez to make 135lbs, and he was certainly edgy during fight week but he was a big favourite coming in against the Australian. Kambosos talked the talk so well all week, but many didn’t expect him to be able to walk the walk.

It was a huge upset, and over the years I have seen many. But it seems to be a more common occurrence in boxing today, especially with fighters having long lay-offs due to the pandemic. Only recently in Sheffield, we saw two huge upsets on our show when Alycia Baumgardner beat Terri Harper and Kiko Martinez knocked out Kid Galahad. Kambosos was always a live dog, but the speed, power and confidence of Lopez made him a huge favourite.

That first round was one of the greatest things I’ve ever seen. Lopez, true to his word, came out as he told the world he would and attempted to stop Kambosos in the first round. He battered him. And with 30 seconds left, Kambosos held his feet, and let a huge right hand haymaker go on the chin of Lopez, knocking him down. That punch shook the garden to its knees.

From there, Kambosos boxed brilliantly. He probably gave away the odd round but then controlled the middle stages of the fight.

Lopez, to his credit, came back into the fight in the ninth, and then had a huge 10th round, knocking down his opponent. To be honest, I thought the fight was over, Lopez looked in full control.

But Kambosos dug deep to win the 11th and 12th in what was an unbelievable performance, and he was the well-deserved winner on the judges’ scorecards.

Lopez and his dad weren’t happy. In fact, I had probably three or four calls and voice notes and messages from Lopez’s dad in the middle of the night, complaining that they should have got the result. I just replied on Sunday morning and said: “Just look at the responses, you lost fair and square.”

For Lopez, he’s still a star, and a great fighter. I expect to see him move up to 140lbs, and I think he’ll be a real threat in the division.

So this week we move on to Las Vegas, and what a run of shows we have coming up. Haney v Diaz for me is one of the fights of the year. I’ve often said that Haney is the best lightweight in the world, so young, so smart, so fast, so slick, so clever. I believe this kid could beat them all.

But this week he takes on a new kind of challenge. Diaz is a two-weight world champion looking to become a three-weight world champion. He’s tough, he’s rugged, and he’s clever. This is going be a brutal fight for Haney.

Unlike Lopez, I know Haney won’t overlook Diaz. This is on paper a much closer fight than last week, but Haney is the ultimate professional. His preparation is always on another level. I’ve spoken to him recently after the Kambosos win, and he’s told me that all he’s focused on is Diaz.

Of course, the fight with Kambosos is there if he wins, and it’s the biggest in the division. That’s the real undisputed championship between two great fighters. If Haney can come through, we’d certainly sit down with Kambosos’ team and his promoter Lou DiBella, and try to get that fight made.

It’s such an amazing time for the division. Not only have you got Haney’s brilliant fight on Saturday, but Gervonta Davis returns on Sunday in what should be a routine victory as well. Right now the new four kings – or four princes as we said last week – are Ryan Garcia, Haney, Kambosos and Davis.

But the fight for the division is Devin Haney against George Kambosos. But only if Haney can beat a very tough and rugged Diaz.

It’s amazing to think that Haney is only 23, with 26 pro fights already behind him. This young man was out learning his craft in Mexico as a teenager, taking early fights in his career, and it’s put him in a tremendous position. He’s spent loads of time in the Floyd Mayweather gym perfecting his craft. This kid is the real deal.