Massú claimed his second ATP title in July 2003 in Amersfoort, Netherlands. The following week, he reached the final of the Kitzbühel tournament, cracking the top 50 in singles for the first time. In September, he made three consecutive tournament finals, including a win at a Challenger event and his third ATP title in Palermo. In October, he reached the final at the Madrid Masters Series tournament, losing to Juan Carlos Ferrero in the final. He ended the year at world No. 12.