The Argentine-born Pernia obtained dual Spanish nationality at the end of April and was the joint top scorer for his club with 10 goals in the Primera Liga last season.

The 29-year-old was initially left out of the squad after coach Luis Aragones said his papers had been approved too late and his inclusion would be unfair on others who had played during World Cup qualification.

Deportivo Coruna's Joan Capdevila had been used as cover on the left and been included in pre-World Cup get-togethers, while Pernia had never been called up.

"Our full backs have to be able to get forward," Aragones told a news conference on Thursday.

"Capdevila is perhaps the best in defence but maybe not in attack. I have a clear conscience because I have taken this decision in the best interests of the team and for what I wanted to do with the team.

"I am sorry for Capdevila and in particular for Del Horno, but I couldn't risk being left with only one left back."

Del Horno damaged the area around his Achilles tendon in training last week and national team doctor Genaro Borras said the player would be out of action for around three weeks.

Pernia, who had set a wedding date for June 20 after he was left out of the squad, will fly back from Buenos Aires and join up with the side in time for the warm-up game against Egypt in Elche on Saturday.

Spain open their World Cup campaign on June 14 against Ukraine, and also play Tunisia and Saudi Arabia in Group H.

Pernia has scored spectacular goals from open play and set pieces in the league, with a stunning volley from outside the area against Barcelona being a contender for goal of the season.

He will be competing with Atletico Madrid's Antonio Lopez for a place in the starting team.

"The two are similar in style. Both are good going forward and are good from dead-ball situations. The best player in training will be the one who gets the nod to start."