Real Sociedad have completed the signing of Borussia Dortmund striker Alexander Isak.

La Real have bought the 19 year-old Swede outright after an outstanding season on-loan with Willem II.

La Real president Jokin Aperribay said: "We have had his eyes on him for a while and welcome Alex to the club.

"We hope he will have a good time here, there are many young players and we hope it will be a good year for the club."

Isak stated: "I felt that the club's concept, where the team produces many talents and gives young players the chance, suits me. It's a good city and a good club, it made it feel like a good choice."

The Swedish youngster has been compared to Zlatan Ibrahimovic.

"I have no problem being compared to Zlatan, I have said it before it is nothing that worries me. I don't feel like 'someone'. I am myself and no one else and do my best, so we will see how far it leads."