18 (August 2003) and finished in the top 50 in the world for seven straight years despite only winning one ATP singles title (2003 Rotterdam Open).

He represented Belarus in Davis Cup competition from April 1994, where he holds a record of 47 wins and 27 losses in 35 ties played.

At the 2012 Summer Olympics in London, Mirnyi carried the flag of Belarus at the Opening Ceremony on 27 July 2012,[2] and won the gold medal in the mixed doubles with Victoria Azarenka on 5 August 2012.

His best performance at a Grand Slam in singles came when he got to the quarterfinals of the 2002 US Open, defeating Attila Sávolt, Antony Dupuis, Dominik Hrbatý and Roger Federer before losing to Andre Agassi.

In the 2004 Davis Cup, he and Vladimir Voltchkov defeated Russia 3–2 and Argentina 5–0, reaching the semifinals, where they lost to the United States.