Mezencev, aged 17, started his career on July 2013. Although still relatively close to the start of his career, his record stands at 8 wins and will hopefully continue to rise. Mezencev's longest KO streak is 8 fights long out of his 8 career fights.
Mezencev proved he was made for the pro ranks in his debut against Anes Valentic, becoming the first person in Valentic's 0 fights to stop him. The fight ended in round 3 of 4. Continuing on from his successful debut, Mezencev won his next 4 fights taking his record to 4 wins.
Marko Rupcic was up next for Mezencev on June 7th, 2014. Mezencev continued with his winning streak by beating Rupcic. Mezencev was the 4th person to stop Marko and he did it in the 1st round via KO. Another win followed for Mezencev taking his win tally to 6 wins.
Mezencev then went on to fight and beat Viktor Szalai on September 26th, 2014 maintaining his unbeaten record. Mezencev was the 35th person to stop Viktor and he did it in the 2nd round via KO.
Ilja Mezencev retained his unbeaten record in his most recent fight by beating Zeljko Bojic on November 14th, 2014, increasing his record to 8 wins. Mezencev's win against Bojic was only the 3rd time Bojic had been stopped. The fight finished in the 2nd round of a 6 round fight via TKO.