I get what you are getting at, tactical nerve and all, but bottom line is, difference in mental blockage is bound to be there when Milan are scudetto champions, and we have been the club that finished 7 two seasons in a row.
I wouldn't blame Genoa for making adjustments.
Milan, as you say, are still a more intimidating prospect than Juve.
However, especially when you factor in home advantage, that's a pretty extreme tactical adjustment to take on Milan.
How did Genoa think they were going to win the game playing like that? They were lucky not to concede five or six, because they let Milan have the ball and didn't even close them down when they had the ball really high up the pitch.
And Milan still looked vulnerable at the back on the rare occasion Genoa actually made them defend a little.
An Aberdeen coach would be chased out of town if he played that negatively at home against one of the Old Firm.