Canelo Alvarez, boxing's biggest superstar, put on a dominant show Saturday night to cap the 2020 major fight slate, cruising to a unanimous decision win over previously undefeated champion Callum Smith and winning the WBA, WBC and The Ring magazine super middleweight titles.

The scorecards read 119-109, 119-109 and 117-111, all for Alvarez.

In front of 15,000 fans (20% capacity) at the San Antonio Alamodome, Alvarez (54-1-2, 36 KOs) stalked Smith (27-1, 19 KOs), punishing him with an array of consistent jabs, uppercuts and hooks for 12 rounds. Alvarez became the first unified champion from Mexico in super middleweight history.

"I'm the best in the world," Alvarez said on the DAZN broadcast via an interpreter. "In the first round, I tried to see what he brings, the skills or whatever, but like you can see, I showed what I am."

By the later rounds, the intrigue of the fight shifted from who would win to whether Smith would survive Alvarez's lethal blows and make it to the distance.

The 6-foot-3 Smith had a 7-inch height advantage and 8-inch reach advantage over the 5-foot-8 Alvarez, but it didn't matter, as Alvarez was the big bully Saturday night, eliminating the distance that Smith prefers and consistently pounding punches off his head and body.

"He was the better fighter tonight," Smith said. "He's smart. He's clever. He sets you little traps and keeps you thinking. Before you know it, he's closing the ground. He's a good fighter, but I'm just a little disappointed with myself. His jab was really good. It surprised me a little bit. His defense was really good."

Alvarez has now defeated two Smith brothers -- knocking out older brother Liam Smith as a junior middleweight in 2016 and defeating Callum Smith on Saturday.

Alvarez, universally considered one of the top two pound-for-pound boxers in the world, boxing's best-selling fighter and already a four-division champion, now has won The Ring magazine title in three different weight classes. He landed 43% of his punches and 57% of his power punches Saturday, per CompuBox, in a complete performance in which his defense also shined. Smith landed only 18% of his punches and 24% of his power punches.

It was Alvarez's first fight since parting ways with Golden Boy Promotions and DAZN after contractual disputes, and he returned to the ring for the first time in 13 months as his own promoter with little in-ring rust.

"I'M BACK!" he wrote as part of a Twitter post early Sunday morning.

I'M BACK! ?
✅ WBC Super Middleweight Champion
✅ WBA Super Middleweight Champion
✅ Ring Magazine Super Middleweight Champion#CaneloSmith #TheP4PKingIsBack@CANELOTEAM pic.twitter.com/dQjrwXWcQZ

— Canelo Alvarez (@Canelo) December 20, 2020

Even at 30 with 57 pro fights, Canelo still looks firmly in his prime. He's still intimidating opponents, with fighters often shifting into survival mode once feeling those blows, and it's becoming hard to find anyone in the super middleweight division who can give Alvarez a true threat.

But Alvarez said after the fight that he feels great in the super middleweight division, noting he doesn't want to fight with the scale. His main goal is to unify all the belts in the division. Billy Joe Saunders currently holds the WBO belt and Caleb Plant has the IBF belt. But the bigger lingering question is whether Alvarez will agree to a trilogy fight with Gennadiy Golovkin after two highly contested fights that ended in a draw and an Alvarez win.

"I don't run from nobody. I just showed that I fought against the best," Alvarez said. "If he's going to take the fight, I'll take it. But I just showed I fight against the best."