Spurs and Celtics are both undefeated at home. Which team will lose a game first?

Regardless of what the Celtics do against the weak Eastern Conference teams, they will lose at home to a stronger Western Conference team. Before we crown the Celtics as champs, lets see how they do against the Best of the West. I strongly believe that the Celtics will lose at home first due to the fact that they lack a TRUE big man in the middle. KG is not a big man.