Petrov joined Celtic from CSKA Sofia in 1999, and stayed with the club until he moved to Aston Villa in the Premier League, along with his former manager Martin O'Neill.
Petrov joined Celtic from CSKA Sofia in 1999, and won ten trophies in his time at Celtic Park, including four Scottish Premier League titles. In 2006, he moved to Aston Villa in the Premier League, along with his former manager Martin O'Neill.