I will go with @Docnaster here with his opinion of Spain this year not having the usual experienced team as we use to see them on most previous World Cups, if you say that they didnt give their best on the match against Japan thats not a reason because for few minutes when Costa Rica was winning against Germany, Spain was out of group stage if the score remained the same.
I believe Spain is just not strong enough this year and Morocco may have a great opportunity to win the match
Morocco has not qualified for the round of 16 since 1986, and I do not think that it will exit from the current tournament early. Walid Regragui is a graduate of the Badou Zaki Academy, In his match against Spain, I expect him to put up a defensive formation and play on counterattacks. The Spanish national team has become difficult to dismantle the lanes, as for the defensive teams, so my bet tomorrow will be in favor of Morocco, with good odds @ 7.40

Spain went down against one of the weakest teams in the tournament (Japan). So I would say that definitely there is a chance (irrespective of the betting odds). This match is going to be an emotional issue for both the teams as well (both the countries have tried to colonize each other in the past). Anyway, Morocco is the last remaining team from AFC/CAF having a chance to qualify to the QF stage. If they are defeated today, then the quarter-finals would feature teams solely from the CONMEBOL and UEFA confederations.