Real Madrid came out of injury and still didn't perform. From what i remembered, Madrid played most games using their best squad that means they had the chances but couldn't pay out their effort. Injury isn't sounding like an excuse for me, Madrid were not good last season and now is the best time for improvements.
You sound like a person who knows nothing about Football. How do you expect a player or players who have been sidelined for months to come in as substitutes in a match and perform so well instantly?
Injuries are not an excuse and can affect any team at any time and there's nothing you can do about it except try to make some transfers during the transfer windows to cover up the void.