Like this bet a lot. Isner have an enormous serve and he will probably start serve here so he can afford to get broken once. Isner isnt a good returner and in play will Nadal have edge so i have troubles see Nadal got broken here early. Isner didnt face a bp vs Querrey and had 79% first serve, even the best returner in the world will have problems with that serve. Should easily be 10 or more games first set.