Russia's Murat Gassiev retained his IBF cruiserweight belt and grabbed the WBA cruiserweight title with a technical knockout of Cuban Yunier Dorticos in a unification bout in Russia's resort city Sochi on Saturday.

Gassiev, 24, the youngest member of the cruiserweight field of the World Boxing Super Series (WBSS) improved his record to 27-0 with 19 KO's following the semi-final win in Sochi's Bolshoy Ice Dome.

The 31-year-old previously unbeaten Dorticos -- nicknamed "The KO Doctor" -- has now dropped to 22-1 with 21 knockouts.

Dorticos started confidently trying to control the pace of the fight from the start. He performed some good jab work, while Gassiev also landed effective punches in the opening round.

The Cuban continued to push the pace with the hard punches in the second but Gassiev replied positively landing some more solid shots of his own into his opponent's body.

Later on Dorticos continued peppering his rival with shots but his unvaried attacks made little headway as Gassiev defended stoutly responding with rare but hard and precise punches.

After the eighth round Dorticos' work rate noticeably slowed down and Gassiev stepped up the pressure, beginning to take control and show off his superior hand speed and precision.

Dorticos would like to get a rematch.

"Murat is a strong fighter, we would like to have a rematch with him. I want to thank Sochi for the wonderful reception, it was a great fight. This is a heavy defeat, but I will return," Dorticos said.

"It's a very emotional fight, it's very difficult to lose these types of fights, yet I wanted to congratulate the whole team, they deserve it."

In the final round Gassiev looked in complete command sending Dorticos to the cavas twice before the referee stopped the bout with just 18 seconds remaining.

Next stop for Gassiev is the Muhammad Ali trophy in the cruiserweight division of the WBSS final in Jeddah, Saudi Arabia in May.

There he will face Ukraine's Alexander Usyk, who beat Mairis Briedis of Latvia in the other WBSS semi-final.