At the beginning of this year, middleweight boxing superstar Canelo Álvarez was widely considered the best pound-for-pound fighter in the world. But to the surprise of pugilism pundits worldwide, Álvarez slipped. In May, Dmitry Bivol of Russia upset Álvarez in a light-heavyweight matchup, handing Álvarez, just the second loss of his professional career.

All which makes tonight’s fight, between Álvarez and Gennadiy Golovkin in Las Vegas, all the more crucial for Álvarez. The Mexican boxer is already one of the most influential fighters of the 21st century. In 2018, he inked staggering 11-fight, $365 million fight deal with DAZN, a new sports media entity that had just launched. Álvarez, who hails from Mexico, trains in Southern California and has homes in both San Diego and Guadalajara, is popular throughout North America. Although his original DAZN deal fell through, Álvarez, 32, re-upped with DAZN for a lucrative two-fight deal in February.

“This fight is very important for my career,” Álvarez told TIME in a pre-fight interview. “Golovkin is a great fighter with a lot of accomplishments. This fight is important for my legacy, to be remembered as one of the greatest fighters in boxing history.”

These two fighters share a history. In 2017, they met for the first time in the ring, and the bout ended in a controversial draw; although Golovkin connected on 50 more punches than his opponent, one judge called it a draw, another gave Golovkin the fight, and one judge turned in a baffling card for Álvarez, scoring the fight 118-110 in his favor. It was one of the richest fights in the history of the sport: it sold more than $27 million in tickets, and attracted more than 1.3 million pay-per-view buysคำพูดจาก 8อันดับเว็บสล็อ. A rematch was announced in January of 2018, but about two months before the early May fight date, Álvarez tested positive for a banned substance, clenbuterol. He blamed the result on meat from Mexico, an excuse with precedence. An NFL player, Duane Brown, had a potential clenbuterol suspension overturned around 2016, successfully arguing that the positive test resulted from eating tainted Mexican beef. The Nevada State Athletic Commission still suspended Álvarez for six months, and the rematch was rescheduled for Sept. 15, 2018.

The incident is still a source of bad blood. Golovkin has never believed Álvarez’s contention that he unintentionally used a banned substance “I’m more concerned about the situation from the standpoint of my opponent claiming to be one of the best fighters, one of the best representatives of the sport, and at the time behaving as if violating this once is still ok,” says Golovkin, who’s from Kazakhstan, through an interpreterคำพูดจาก บเว็บสล็อ. “This is disappointing.”

“I did everything to prove that I didn’t do anything wrong,” responds Álvarez. “That’s fine. That kind of thing, it’s excuses and excuses and excuses. I hate that motherf—er.”

Álvarez won that rematch, in another close bout. Boxing should have completed the trilogy soon after this 2018 fight, but as it the sport’s wont, all kinds of sniping got in the way. So fans had to wait four years for the third fight. Golovkin’s now 40.

But don’t let age belie intensity. Given the rivalry between these two fighters, you can expect a slugfest tonight.

“I’m motivated,” says Golovkin. “I don’t really care about what he says, what he does, how he dresses. I know this opponent. I know Canelo. I know his level as an athlete. But I’m sort of disappointed with his behavior. As a person, he failed to develop himself to be a better man.”

Ding ding. The bout begins around 11 p.m. Saturday in the eastern U.S.