Hall of Fame boxer "Sugar" Shane Mosley said Friday that he finished in the red after fighting Canelo Alvarez in 2012.

Appearing on Triller's OK Bet with Mario Lopez (h/t TMZ Sports), Mosley said he bet $1 million on himself to beat Alvarez despite only getting paid $600,000 for the fight.

That decision didn't work out well for Mosley, who was 40 years old at the time and fighting the 21-year-old Alvarez. Mosley lost a one-sided unanimous decision, resulting in Alvarez remaining undefeated at 40-0-1.

Mosley explained his line of thinking at the time of the bet, saying: "I was thinking this snot nose kid is not gonna beat me, you know at 154 [pounds]."

He also remarked that he essentially had to pay $400,000 for "getting my butt kicked."

Even then, Mosley seemed like a long shot to win, as Alvarez was one of the fastest-rising stars in the sport. He had beaten Matthew Hatton to win the vacant WBC light middleweight title four fights prior and was on a three-fight knockout streak entering the clash with Mosley.

While Alvarez was undefeated at the time, Mosley was 46-7-1 entering the bout and had suffered two losses and one draw in his previous three fights.

Mosley was a top-flight boxer in his prime, holding the WBC and WBA (Super) welterweight titles, and beating the likes of Oscar De La Hoya, Fernando Vargas and Ricardo Mayorga.

He often struggled against the best of the best, though, losing to Vernon Forrest, Winky Wright, Miguel Cotto, Floyd Mayweather Jr. and Manny Pacquiao prior to the Alvarez fight.

Despite that defeat, Mosley still enjoyed a great career and fought five more times after, going 3-2.

Mosley's final contest was a unanimous-decision loss to Russia's David Avanesyan for the WBA interim welterweight title in 2016.

Sugar Shane retired with a 49-10-1 record, and he is now focused on the boxing success of his son Shane Mosley Jr., who is 17-4 with 10 wins by way of knockout.

Meanwhile, Alvarez has developed into one of the biggest stars in boxing, owning a career mark of 51-1-2, with his only loss coming to Mayweather.