MONTREAL, Canada (AFP) — Undefeated Artur Beterbiev defended three world light-heavyweight boxing titles by stopping Britain's Callum Smith in the seventh round on Saturday, winning by knockout for the 20th time in as many fights.

Beterbiev, a 38-year-old Russian-born Canadian, stopped the Englishman after two minutes of the seventh round in Quebec City, Canada, improving to 20-0 and remaining the only world champion to win every fight by early stoppage.

A hard right hand by Beterbiev to the side of Smith's head was the stunner that set up a series of punishing lefts to the head and a final right-left combination crumpled the Englishman to the canvas for the first time in his career at any level 70 seconds into the seventh round.

Smith rose against the ropes but Beterbiev quickly landed a five-punch combination to drop the challenger to the canvas again. Smith's corner halted the bout moments later.

Beterbiev retained the World Boxing Council, World Boxing Organization and International Boxing Federation light-heavyweight crowns and set the stage for a likely undisputed unification fight with unbeaten World Boxing Association champion Dmitry Bivol of Russia.

Smith, a 33-year-old former WBA super middleweight champion, fell to 29-2. His only prior defeat was by unanimous decision in 2020 to Mexican star Canelo Alvarez, the undisputed world super middleweight champion.

Beterbiev was to have faced Smith last August but the fight was postponed after a bone infection required Beterbiev to have jaw surgery.

Beterbiev, who won his first world title in 2017, defended the three titles for the second time, having stopped Britain's Anthony Yarde in the eighth round last January in London in his most recent bout.

Smith last fought in August 2022 when he stopped France's Mathieu Bauderlique in the fourth round to earn his chance against Beterbiev.

The home-region favorite is expected to fight for an undisputed 175-pound (79.9kg) division crown against Bivol, 33, who is 22-0 with 11 knockouts.