Sanches ended up joining Bundesliga giants Bayern for a fee of £27.5m.
And Rummenigge has shed light on why that might be the case.
"This is a tremendous amount of money, something we do not need to discuss, but I sat down with Carlo Ancelotti in March and we agreed: this player is worth the risk," Rummenigge said.
"At the European Championship it has already been seen what tremendous power he brings, and what a personality he is on the pitch at 18. That’s impressive.
“When Renato Sanches became known at the European Championships, he had already signed with us.
“We won [the race] for his signature because the others had just planned their holidays.”
United finish off their pre-season preparations with a Community Shield showdown against reigning Premier League champions Leicester on Sunday (4pm).
Invalid email
We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy