Saul 'Canelo' Alvarez overcame Billy Joe Saunders and wants to become super middleweight's first undisputed champion next.
The Mexican added the WBO belt to his WBA, WBC and Ring Magazine titles and Caleb Planet's IBF crown is the remaining title for him to capture at 168-pounds.
Mark Tibbs - trainer of Saunders - halted the fight after the former two-division world champion sustained a horror injury to the right eye.
It is believed Saunders suffered an orbital bone fracture from a thunderous uppercut by Canelo.
At the time of the stoppage, which inflicted the first defeat of Saunders' 31-fight professional career, the scorecards read 78, 74, 78-74 and 77-75 in favour of Alvarez.
If you were to believe the scoring by the judges, influenced by a sold-out AT&T Stadium in Texas, then you would have presumed it was a one-sided beating by boxing's Pound for Pound king but it could not have been further from the truth.
Not one to miss a trick, Canelo reminded the world of his Mexican heritage as he was welcomed out by a full mariachi band to celebrate Cinco de Mayo weekend.
Saunders, who walked out first, was accompanied in the corner alongside good friend and heavyweight king Tyson Fury, who will confirm his fight against Anthony Joshua this week.
Following a pedestrian opening three minutes, the next two rounds Saunders was under the cosh with Canelo landing heavy punches to the body and head.
His left hook to the body and right uppercut were the two shots delivering the damage in the early rounds as Saunders backed up onto the ropes several times.
With the writing seemingly on the wall, a determined Saunders came out in the fourth round with some promise and looked more mobile, much to the delight of Tibbs and Ben Davison.
Confidence grew in round five and "Superb" was finally finding his momentum in the fight and threw some successful combinations before landing two unanswered left hooks, the second being after a clinch.
Saunders had found his range and by round six, his jab and head movement dictated a good three minutes followed by some impressive inside work in the next round.
Withstanding the continued pressure by Canelo, Saunders' was in rhythm with his jab and left hook proving a successful combination.
Rolling his tongue out during the round, Saunders appeared to be enjoying himself in front of a pro Canelo crowd which included Dallas Texans' owner Jerry Jones.
By round eight, Canelo had one thing on his mind - to knock Saunders out - and after upping the pace with a left hook the body, the four-division world champion landed the winning blow by producing a right uppercut to the face of Saunders.
Rocked by the ferociousness of the punch, Canelo raised his hands to some 73,126 fans as they stood on their feet anticipating a stoppage.
Saunders, who threatened to pull out the fight at the start of the week due to the ring size, clinched on for dear life and saw out of the round.
However, with the southpaw's eye swollen badly, Tibbs made the right decision and retired his fighter on the stool. Canelo has now extended his record to 56-1-2.
What's next for Canelo Alvarez?
Plant, undefeated with 21 wins, is expected next in September for Canelo on Mexican Independence Weekend.
For the first time in history, all four belts (WBA, WBC, IBF and WBO) will be on the line at super middleweight.
"That's the plan," Alvarez said about fighting Plant next. "That's the plan, to go for the belt. I'm coming, man. I'm coming for the belt. I hope that fight is made easy and we give the fans that fight.
"My personal goal is to unify the titles at 168 pounds," Alvarez said. "Caleb Plant is the other champion and hopefully we can make that fight happen.
"We don't know the [next] goal right now. We don't know what's going to happen then. I want to make history and that's what we're doing right now."
Demetrius Andrade was at ringside watching the fight, wearing a t-shirt that read "Canelo and Billy Joe are scared to fight Boo Boo."
Canelo dismissed the idea of fighting 'boring' Andrade.
"The truth is he hasn't fought with anyone, hasn't fought against anyone, and he's also boring, very boring," Alvarez said.
"Maybe he's a good fighter, but he's a boring fighter, and at the end of the day, when there's a boring fight, people are going to blame me.
"I like fights where there's action, where people can enjoy a good show. That's very important for me. But also he doesn't represent a challenge for me, as well, because he hasn't fought against anybody."
What's next for Saunders?
First of all, he has to recover from a broken eye socket. As we have seen with previous fighters - Kell Brook being the prime example after his devastating defeat to Gennadiy Golovkin - it is hard to recover from an eye injury.
There are plenty of fights for Saunders, who proved not only to be competitive in the fight but also a pay-per-view attraction.
A tune-up fight would be required next but a rematch with Chris Eubank Jr. is a viable option while Andrade and middleweight great Golovkin are also opponents fans would love to see Saunders in the ring with.