Mairis Briedis won the WBO world cruiserweight title after elbowing Krzysztof Glowacki in a controversial Super Series semi-final in Latvia.
Briedis, the home favourite, floored Glowacki with an elbow to the head with 40 seconds left in the second round.
But referee Robert Byrd ordered the Pole to his feet before he was knocked down twice in the same round, with the second coming after the bell in Riga.
Briedis then ended the bout with a strong right hand in the third round.
Following the fight, the Latvian said his "dirty" shot was in response to a punch by Glowacki on the back of his head, after Byrd ordered the fighters to pause following a coming together.
"I think the referee didn't do nothing, then I did a little bit of a dirty punch but I'm sorry for how I responded, it's my old Muay Thai style," said the 34-year-old Latvian.
Briedis will now fight in the final against IBF champion Yunier Dorticos, who knocked out Andrew Tabiti in the 11th round of their semi-final of the World Boxing Super Series.
Both the WBO and IBF belts will be on line for the final of the Super Series, which was won by Oleksandr Usyk last year.