On 28 June 2006, he transferred to Zenit Saint Petersburg, following coach Dick Advocaat and Korean teammate Lee Ho. In Zenit, both his performance and reputation grew steadily, making him the key side defender in the starting lineup. He helped Zenit to achieve their first Russian Premier League title and most reputably the UEFA Cup. His outstanding improvement in his club and national team brought his reputation as the best left-back in the current Korean squad. On 26 January 2010 Zenit Saint Petersburg terminated his contract based on results of the medical examinations and fainting spells experienced during practices with the national team.