Tonight at 6:00 p.m. ET at the MGM Grand in Las Vegas, Floyd Mayweather Jr. (48-0, 26 KO) will step on the scale, as will Andre Berto (30-3, 23 KO), before they face one another inside the ring Saturday night. Fans can watch the live stream below.

Mayweather has received a lot of criticism for choosing Berto as his opponent for this fight, which he claims will be his last. It is the final bout of a historic six-fight, revenue-sharing contract he signed with Showtime in 2013, and a victory would push his record to 49-0, tying the mark of heavyweight legend Rocky Marciano.

The fact that Mayweather would choose an opponent as flawed as Berto in an effort to tie Marciano’s record has rankled the feathers of fight fans. Berto is just 3-3 in his last six fights; two of the losses were against Victor Ortiz and Robert Guerrero, two fighters Mayweather has already beaten. The third was by knockout against Jesus Soto Karass, who had eight losses when they fought, and currently has 10 defeats on his resume.

Others believe Mayweather is biding his time for a 50th fight –perhaps a rematch vs. Manny Pacquiao –but Mayweather continues to deny that, and push the narrative of Sept. 12 being the last time to witness an all-time great in action.

"I'm ready to hang it up and spend time with my children," Mayweather said. "Most fighters that are retired didn't have a choice.”

The positives about Berto are offensive. He has good power for a welterweight, fast hands, and a warrior mentality. The problem is that Berto routinely displays poor technique, and Mayweather is a near-perfect tactician. Berto throws power shots that take him off balance, while Mayweather is an expert counter-puncher. All the information favors Mayweather, and Las Vegas oddsmakers agree; they’ve installed Mayweather as a -4,000 favorite.

Despite all that, the refrain is the same. It ends Saturday.

"They want to know if I'm retiring? Absolutely," Mayweather said. "No. 49. That's it. I'm not sad at all this is my last show."

Also weighing in:

Roman Martinez vs. Orlando Salido
Badou Jack vs. George Groves
Jhonny Gonzalez vs. Jonathan Oquendo