Saul 'Canelo' Alvarez became the first undisputed super middleweight champion in boxing history after knocking out Caleb Plant in the 11th round of their blockbuster showdown.

All eyes were on Las Vegas for Saturday's unification bout between WBA, WBC and WBO holder Canelo and unbeaten IBF champion Plant.

Canelo (57-1-2) claimed a clean sweep of the division belts after a merciless KO of Plant at MGM Grand, where the Mexican superstar inflicted a first professional defeat on the American.

The aggressor, Canelo had a sniff of blood in the penultimate round after flooring Plant (21-1) and that was all he needed as he hunted down his opponent before landing another knockdown.

Canelo was on the hunt from the very first bell, holding his ground and seeking an opening as Plant fought off the hunter with his jabs.

Working the body was the theme for Canelo, who put Plant under mounting pressure in the second round, though the latter went to work quickly in the third with a jab and hook.

Plant continued to move well but there was no escaping Canelo as he used a combination to lay into the former in the fourth.

A lack of power was problematic for Plant, who did not have enough on his punches to back off Canelo and really hurt him.

While Plant was still throwing punches, Canelo was simply unbothered on the hunt with a hard uppercut.

Canelo rocked Plant in the sixth round, backing him into the ropes before a three-punch combo put the three-belt champion in a powerful and brutal rhythm.

Amid a restless crowd, Canelo wore down Plant as he gave his opponent little room to breathe while maintaining his aggressive approach heading into the 10th round.

It all came to a head in the 11th as Canelo flexed his muscles to write his name in the history books.