Although his career was cut short due to a debilitating back injury, he is one of the few professional boxers to win a world championship and retire undefeated.

At the early stages of his amateur career he didn't have a trainer, instead he studied carefully VHS tapes of Sugar Ray Leonard and later Floyd Mayweather Jr., which affected his style heavily.

Pirog came in as a relatively unknown contender to American audiences, while Jacobs had the overwhelming backing of manager Al Haymon and promoters Golden Boy,[4] as well as a very high knockout percentage.

Jacobs was unable to get back up and the referee waved off the fight, giving Pirog a knockout win and making him the new WBO middleweight champion.

[10] Several comeback attempts by Pirog to face Golovkin on an HBO pay-per-view main event were thwarted by ongoing back problems, effectively forcing his premature retirement.

[1] In March 2017, Pirog replaced Alexander Metkin in the State Duma, the Russian lower house, representing governing party United Russia.