So far the games that Real Madrid are playing aren't that hard and Barcelona didn't lose any point. We should wait until the end of September to see Real Madrid facing Atletico Madrid then playing against Villarreal to take more ideas about how good Xabi Alonso managed the team and obviously by the end of October, a clear conclusion will be taken after facing Barcelona. I doubt until then Real Madrid will lose any game.
Yes, they have not yet faced an opponent that can judge them. However, it is clear from the last few matches that Real Madrid are not at their best, which is why they are not able to score big against smaller teams and do anything to distinguish themselves. Maybe when they face Barcelona, we will be able to see how much Real Madrid have improved this season and whether they are the first choice to win the title. Even our doubts about Xabi Alonso will be cleared. Before playing Barcelona, they will play against some teams that are a bit difficult to win against and that will also be a way to judge their strength.