[3] He won a bronze medal, along with his brother Andrey Mazunov, in the men's doubles at the 1991 World Table Tennis Championships in Chiba, Japan, representing the Soviet Union.

[5][6] In the men's doubles, Mazunov and his brother Andrey lost the quarterfinal match to South Korea's Kim Taek-Soo and Yoo Nam-Kyu, with a set score of 0–3.

[7][8] Representing Russia at the 1996 Summer Olympics in Atlanta, Mazunov lost the first round match of the men's singles to Belarus' Vladimir Samsonov, with a set score of 0–3.

[9][10] In the men's doubles, Mazunov and his partner Andrey placed second in the preliminary pool round, receiving a total score of 120 points, two victories from Belarus and the United States, and a single defeat from the South Korean duo Lee Chul-Seung and Yoo Nam-Kyu.

The Russian pair narrowly lost the bronze medal to the Danish duo Michael Maze and Finn Tugwell, receiving a final set score of 2–4.