Robert Helenius stopped Sergei Liakhovich in the ninth round of a scheduled 12-round heavyweight bout on the Alexander Povetkin-Ruslan Chagaev card Saturday in Erfurt, Germany.
Helenius (16-0, 11 knockouts) has stopped 10 of his last 11 opponents.
The 6-foot-6½ Finn, who fights out of Germany, and Liakhovich (25-4, 16 KOs) fought on fairly even terms for seven rounds in a give-and take fight even though Helenius seemed to outwork his foe.
Helenius took control in the eighth, when he forced the former WBO titleholder to take a knee with a vicious combination.
Liakhovich seemed to have recovered at the start of the ninth but a perfect left uppercut and five quick follow up punches put Liakhovich down again the fight was stopped 19 seconds into the round.
Liakhovich has now lost three of his past five fights, after falling to Shannon Briggs in 2006 and Nikolai Valuevin 2008.
He is from Belarus but lives and trains in Scottsdale, Ariz.
Povetkin outpointed Chagaev earlier in the night to win what the WBA calls its "regular" title. Wladimir Klitschko is the WBA titleholder.