Martins signed a long-term contract with Inter Milan in 2005 which ran until 2010 and was worth around €2.5 million annually. By scoring in the 3–1 win at Anderlecht in the 2004–05 UEFA Champions League group stage, Martins become the first ever teenage to score in three consecutive Champions League seasons. He was also protagonist in team's successful run in Coppa Italia, scoring six goals, including a hat-trick against Bologna, as the tournament ended in conquest. Martins amassed 22 goals in 45 matches across all competitions, setting a new personal best; his good form for Inter earned him a spot in Nigeria's 2006 Africa Cup of Nations squad.