I'm seeing this game that none of the two side, Barcelona or Madrid would want to let go of this 3 points for the other, If you could recall, Real Madrid last Major match was against Atletico Madrid that game end on a draw, I don’t really see that Madrid would want to lose this game to their major rivary team in Spanish La Liga, Barcelona and losing to Barcelona means they have given Barca more opportunity to be the Champions this season.
For someone who wants to bet on this match should consider going for over 2.5 goals, because this is what I have had paid off most the time during El Clasico games.
Sure both team won't want to let go the 3 points because it will really determine their fate in race for the league title, Realmadrid is going to be facing Celta Vigo next which isn't much of a big deal for realmadrid ), for borussia dortmund game, they've always won them and I belief they could still win it or draw at worse(lowprob of draw), if Realmadrid handles Dortmund without too much stress then there should be some clear prediction towards Barcelona game.
Barcelona on the other hand, is going to be taking on Sevilla (sevilla ain't an easy team but I know there will be some goals to compete), next is Bayern if Bayern doesn't weaken or give players injury then playing Realmadrid could be a little bit fair for them but it's still going to be an hard game for both side, they both need the point either they win the successive match before or not but a draw is still going to favour Barcelona if they win the match against sevilla so the goals
might not flow