On Sunday in Moscow, former World Boxing Organization (WBO) junior welterweight champion Ruslan Provodnikov returned to the ring for the first time since 2016 - and won a five round split decision over UFC title challenger Ali Bagautinov.
The contest was fought under boxing rules as part of a big charity event.
After the fight, the 37-year-old Providnikov made it clear that he was retired and had no intention of coming back in a sanctioned fight.
Earlier this year, there were rumors that he might resume his career.
“I just want to say that I've ended my career. Fate gave me such a path in life. I want to thank you for everything,” Provodnikov said.
Provodnikov owned the WBO championship from 2013 to 2014, and the last pro fight of his career took place in mid-2016 - when he was outboxed over twelve rounds by John Molina.
After the fight with Molina, Providnikov stepped away from boxing and began to steer his attention to the political scene in Siberia.
He often hinted at the possibility of fighting again, but nothing was ever seriously pursued.
During his career, he won 25 fights in the professional ring (18 by knockout) and suffered five defeats.
His bouts against Timothy Bradley and Lucas Matthysse are regarded as two of the most bruising fights of the last decade.
Bagautinov is a year younger at 36. His pro record includes 21 victories in mixed martial arts (MMA) and seven defeats. In 2014 he attempted to become the first Russian fighter to win a world title in the UFC - but he lost a five round decision to Demetrious Johnson.