Josh Taylor learned a huge lesson in previous fight that will make him better Saturday against Teofimo Lopez

Josh Taylor is one of the most accomplished fighters in boxing. He enters Saturday's WBO super lightweight title bout at Madison Square Garden against Teofimo Lopez with a record of 19-0 with 13 KOs. Many regard him as one of the top 10 pound-for-pound boxers in the world, and those who don't have him in the top 10 have him just outside of it.

But Taylor returns to the sport and the division that he dominated with much to prove. He learned a harsh lesson last time out in a split decision victory over Jack Catterall on Feb. 26, 2022, that rubbed some of the shine off the undisputed title he'd won in his previous bout against José Ramírez.

It wasn't so much that Taylor struggled in the fight. It was more about the process. For a guy who had never been cocky and had never failed to prepare diligently, he failed on both counts against Catterall.

"I made a mistake that a lot of athletes have done in the past," Taylor told Yahoo Sports. "I have tried to learn from what some of these fighters had done in the past, which is complacency and looking past your opponent, underestimating him. I've always said, 'You never underestimate anybody.' But I firmly believed that Jack Catterall was five levels below me and that was the mentality that I had going into the fight.

"I'd just been to Vegas and conquered the world and had become the undisputed champion. And [against Catterall], it felt like I was coming back to fight a domestic-level fighter. That was the mistake I made. I came back from Vegas and I never saw the inside of a boxing gym for a couple of months. I put on too much weight and was eating too much good-tasting bad food, drinking a little too much beer and enjoying life, enjoying the victory. ... I got back into the gym and I was soft, fat and unconditioned, and I spent most of the camp trying to get back into condition."

A source inside Taylor's camp told Yahoo Sports that Taylor is already on weight, five days out from fight night. He's giving Lopez, the former undisputed lightweight champion, the respect he did not have for Catterall.

Lopez has been one of the best fighters in the world, but he's been enigmatic and suffered mental health issues as well as physical injuries that have hampered him somewhat.

At his best, Lopez is a powerful and dangerous opponent. Taylor said he's prepared diligently because he knows what Lopez is capable of doing.

"This fight puts that fire back in my belly," Taylor said. "It gives me the desire and the hunger. I've got the excitement because you don't know what's happening. You need that to perform at your optimal best. You need these feelings inside your stomach to perform at your best. You need that little bit of nerves. You need that little bit of fear. You need that little bit of hunger and desire and excitement, as well. I never had any of that for the Catterall fight. I was like, 'Come out, be fit, job done.'

"That was the big mistake that I made, but I'm not making it again."

This could come down to a battle of mental strength, because each knows how good the other is. Lopez made a ridiculous comment that he wanted to kill Taylor, which is inappropriate even though it came in the course of trying to push the fight.

Taylor, though, believes he has a huge advantage over Lopez in mental toughness and dumped on Lopez's team, particularly his father/trainer Teofimo Lopez Jr. He said Lopez Jr. "is a nut job" and "probably still heavy on the booze."

Nonetheless, he respects Lopez and said it's a "blockbuster fight" because of what Lopez has accomplished. With a win, Taylor said he'll have options and listed undisputed lightweight champion Devin Haney, WBC super lightweight champion Regis Prograis, former champion Ryan Garcia, secondary lightweight champion Gervonta Davis and welterweights Terence Crawford and Errol Spence Jr. as potential bouts for him.

But first, he has to get past Lopez and said his mental toughness will be one of his significant advantages.

"Listen, I'm mentally stronger than all of my opponents and I'm certainly mentally stronger than him," Taylor said. "He seems a little bit all over the place and unsure of himself. He's very confident on camera and very confident on social media and stuff, but I know that's a front and he's just putting on a facade. He's got those feelings inside him and I know he's mentally weak. I'm not taking too much from it, but I know I'm mentally stronger than this guy and when the fight gets tough, he's going to be the one who's going to be quitting. He may have a bit of quit in him."