Cristiano Ronaldo and Mesut Ozil gave Los Blancos the victory over the Premier League club in Los Angeles.
But the Italian tactician admitted after the match that his men have to improve.
“We have to play better football,” he told a Press conference.
“We could have been better is some areas, especially in the second half.
“However, it is understandable because we were a little tired after having played two days ago.
“The first half was good, we played well and scored two goals. The second half was more difficult because we had played another match two days ago.
“But at this point in the preseason the most important thing is not to have injuries.”
The Santiago Bernabeu side now travel to Miami to play either Milan or Chelsea.
“The next match will be special,” he added. “Playing against either opponent will be good.”