Yourassowsky began his career in the youth ranks of top Belgian club Anderlecht. In 2001, he went on trial for four months with top Spanish side FC Barcelona. He returned to Anderlecht and in 2003 joined Genk. After impressing in Belgium, Yourassowsky joined top Argentinian side Boca Juniors. He was promoted to the first team by Carlos Bianchi and made his first division debut in June 2004 in a starting role in a 0–0 draw versus Colón de Santa Fe. As a result of injuries and a managerial change his opportunities with Boca diminished.
