Semak started training football at the Luhansk football school. In 1992, he signed in
Presnya Moscow who played in the
Russian Top Division. After 19 matches scoring 4 goals he was sold to
Karelia Petrozavodsk, but in 1993 returned to Presnya Moscow, which had changed its name to
Asmaral Moscow. In 1994, Semak was noted and signed by
CSKA Moscow. He became the club's captain and leader. With the club he won the
Russian Premier League in 2003, the
Russian Cup in 2002 and 2005. He left the club after it finished third in the group stage of the
UEFA Champions League 2004–05 and did not move on to the knockout stage. This was despite his hat-trick against
Paris Saint-Germain in the final group game. In 2005, Semak then moved to the team he scored the hat-trick against, Paris Saint-Germain, but failed to settle, scoring just one goal. After just one season he returned to Russia. In 2006, Semak signed for
Moscow, where he stayed until 2008 when he moved to
Rubin Kazan. In Rubin Semak was moved from the positions of striker and attacking midfielder to the position of a defensive midfielder. At Rubin Kazan he became the captain and leader of the team, and led it to its first two championship titles in 2008 and 2009. In August 2010, he transferred to
Zenit Saint Petersburg. In his three seasons with Zenit, he won the
Russian Premier League twice and
Russian Super Cup once. He scored his last goal in February 2013 in a
Europa League victory over
Liverpool. ==International career==