In the Greek Basket League 2004–05 season, his last season with Maroussi, Spanoulis averaged 15.9 points per game, and shot 37.8% from 3-point range, in 35 games played in the Greek Basket League competition. He then averaged 15.2 points per game, and shot 40.0% from 3-point range, in 12 games of play, in the European-wide 2nd-tier level EuroCup's 2004–05 season. For the year in total, Spanoulis averaged 15.7 points per game, and shot 38.3% from 3-point range, in 47 games played with Maroussi. He played in the 2005 Greek League All-Star Game, and was named to the Greek Basket League's Best Five Team. This was a breakthrough year for Vassilis, as he had averaged 11.1 points per game the previous season. He was considered to be one of the most improved players in Europe for the year. He helped to lead Maroussi to the 2nd place of the Greek Basket League, for the regular season. At the end of the year, Spanoulis was voted the European 6th Man of the Year, and Rookie of the Year in the EuroCup.