As far as I know, most El Clasico ended up with a minimum number of goals. It is because the El Clasico match will be always a tight match. So, each team didn't have too many chances scoring goals. When many key players are unavailable, I assume both teams prefer to play a more defensive. So, I think there will be no many goals, or the match will end up with a draw result.
The condition of the two teams is almost the same, but Madrid seems to suffer more. Let's see, I don't feel confident that Madrid can win because I'm realistic, Barcelona is not a team like last season. Luckily, Madrid will compete at the Bernabeu. They have a supporting advantage, but I don't know yet that many players from these two teams are with the country to fight in the World Cup. So maybe there will be some players who could get injured.