Saul Canelo Alvarez has become a three-weight world champion after knocking down Britain's Rocky Fielding four times in three rounds to claim the WBA "regular" super-middleweight title at Madison Square Garden.

Alvarez, whose first professional titles came at welterweight, went into his first fight at 168lbs as the favourite, despite the fact he was fighting 21lbs and three divisions above where he first established himself.

The 28-year-old Mexican wasted no time in giving his opponent a taste of what was to come, bruising Fielding's ribs with a huge body shot and sending him to the mat in the first round.

The 6ft 1in Liverpudlian recovered to get back on his feet, but the onslaught continued and he was knocked down again by another body shot in the second round.

A blow to the head sent 31-year-old Fielding to the floor for a third time in the third round, and it was when Alvarez's relentless body shots sent Fielding crashing a fourth time that the referee decided he had seen enough.

Fielding, making a first defence of the title he won against Tyron Zeuge in July, managed to exchange some shots with his 5ft 9in opponent in the second round.

But he could not put his height advantage to good use and ultimately was outclassed by the world's highest-paid athlete.

In October, the Alvarez signed a five-year, 11-fight contract worth a minimum 365million dollars (£290m).