Di Stefano said of his fellow Argentine: "I don't know why it didn't happen for him earlier in his career, but I watched him playing for River Plate and was enchanted.
"He's a good option for the Real attack. He has great pace and a good eye for goal."
Di Stefano also said of new coach Bernd Schuster: "He was the best option. We wanted a former player who knew this club well. I hope it all works out well for him."