Radzionau qualified for the men's 50 m freestyle at the 2008 Summer Olympics in Beijing, by establishing a new Belarusian record and clearing a FINA B-standard entry time of 22.72 from the national championships in his hometown Minsk. He challenged seven other swimmers on the ninth heat, including three-time Olympian Camilo Becerra of Colombia. Radzionau edged out Filipino-American tanker and Florida-based resident Daniel Coakley to take the fifth spot by four hundredths of a second (0.04), posting his personal best of 22.65. Radzionau placed twenty-sixth out of 97 swimmers in the preliminaries.