I think friendlies have a different engine to the normal competitions.
I ve played CL final against a much lower opponent and I lost 3-4, when I played them In friendlies it was a disaster for them 6-0.
Khris said something that the game chooses 5-6 protagonists for every team and if your best players aren t selected, they won t do anything in the match so they need to be replaced, or you need to do a drastical tactical change.