[4] On 6 October 2002, Portillo made his first La Liga appearance and second overall for the main squad, starting in a 5–2 home win over Deportivo Alavés[5] and ending that season with five goals in only ten games.

He also scored a vital last-minute equaliser against Borussia Dortmund in the UEFA Champions League second group phase, a goal which ultimately proved to be crucial to reach the knockout stages.

[9] After a successful individual season (12 goals in all competitions, although the Catalans were relegated from the top flight),[10] in July 2007 Portillo replaced at Osasuna Roberto Soldado, who returned from loan to Real Madrid.

In late December 2009, Portillo – who was only fourth or fifth-choice striker for Osasuna coach José Antonio Camacho[12]– finally moved clubs, signing until the end of the season plus two more with Segunda División's Hércules CF.

After some time to adjust he finished in the starting XI, netting vital goals in the final stretch, including one in the last round for a 2–0 victory at Real Unión as the Alicante side returned to the first division after 13 years.