WATCH: Mexican great Canelo chases US rival Plant around ring before brutally knocking him out to be crowned undisputed king

Mexican icon Saul ‘Canelo’ Alvarez cemented his legacy as a pound-for-pound great by stopping an obdurate Caleb Plant in the 11th round of their super-middleweight title unification fight in Las Vegas.

The previously undefeated Plant posed a gritty challenge for Alvarez for much of the contest at the MGM Grand, but the Mexican remained patient before picking his moment in round 11, sending his rival onto one knee with three thunderous shots.

Plant survived the count and staggered back to his feet, but Alvarez swarmed in with another heavy salvo to send the American to the canvas again.

This time Plant was clearly unable to continue as the contest was waved off and Alvarez, 31, was crowned boxing’s first-ever undisputed king at 168lbs.    

“I respect Plant, he’s a very difficult fighter,” said Alvarez after picking up the 57th win of his 60-fight professional career.

The Mexican star shared a lengthy corner exchange with Plant in a mutual show of respect after adding the Tennessee fighter’s IBF title to his WBC, WBA, and WBO crowns.

Alvarez later said the simmering bad blood from the build-up to the fight was firmly in the past, after the pair had come to blows at a press conference back in September over supposed insults from Plant about his rival's mother. 

Alvarez added the scalp of Plant to his lengthy list of victims. © Reuters

Plant, who was undefeated in 21 fights, had started the bout well in Las Vegas, showing good movement and taking advantage of a height advantage to keep Alvarez at bay with his jab.

Alvarez remained patient as he continued to walk down his rival, refusing to take to his stool in between some of the middle rounds, perhaps in the confidence that he would eventually wear down Plant’s resistance.

The American had shown signs he was still in the contest with some sharp work in rounds nine and 10, but Alvarez ensured the judges were not troubled with a thunderous left hook in round 11 which rocked Plant.

'Sweet Hands' staggered on, but Alvarez did not waste time in moving in for the kill, landing a series of heavy shots to put Plant out of his misery.  

Canelo finished his post-fight press conference with chants of "Viva Mexico!" as the he was crowned boxing's first-ever undisputed champion at 168lbs in the modern four-belt era. 

The only loss on Alvarez's record remains his majority decision defeat to Floyd Mayweather back in September of 2013.

After seeing off the challenge from Plant, attention will turn to who is next on the list of potential victims for the relentless Alvarez.

WBA light-heavyweight champion Dmitry Bivol has been touted as among the options, with the Russian undefeated in his 18 professional outings thus far.

Meanwhile, plaudits poured in for four-weight world champion Alvarez after his display of patient mastery in Las Vegas.