However, his outstanding form has also opened up renewed transfer speculation over his long term future, with Barcelona rumoured to be considering activating his €70M release clause.
But despite the potential interest from Los Blancos, Dortmund have first refusal on the Swedish international, with a €30m buyback option on him.
“We believe that Alex took the right step to go to Real Sociedad and San Sebastián,” Dortmund Sporting Director Michael Zorc told an interview with Marca.
“At first, he impressed as a substitute, scoring goals. This season he has become a regular starter and of course we are following him, but we are happy to have to Haaland in our team.”
However, he is untested in the Champions League, compared to Haaland and Mabppe’s respective European to tier goal records of 18 and 24.