I believe Madrid will probably win this game by 2 to 3 goals, and I don't think they will concede in this match. My reasoning may not be accurate, but I think Sevilla's goals per match stats seem to be only 1:1. This means that Sevilla have a low percentage of scoring goals per game.
Because the senior players are old so their game will definitely slow down because of the age factor and this must be considered about the considerations that Xavi does to new players who will be replaced later, is it possible with existing players (say young players) there will be no motivation if there are no senior players? I think that they should be able to do that because no matter what their task should be an experience as time goes on.
Actually I see two weaknesses of barca at the moment. They have Pique already starting to slow down and midfielder Busquet who is starting to age and xavi has yet to find a replacement. Xavi understands very well his young players are not experienced enough to be alone without them.
Maybe Xavi will take advantage of the winter later to buy new players. They need an experienced young midfielder and central defender.
Real Madrid already has one goal and the game is still going on. I also don't think that Real Madrid will have a hard time against Sevilla because their performance has decreased in the sense that their rotation has decreased so Real Madrid can freely win it.
Because maybe due to a decline in performance so Sevilla have a low percentage of goals I also don't believe they can be in a good position at the end of the season.