Real Madrid host a Malaga side who have flattered to deceive so far this season.
Javi Gracia's XI once again gave Barcelona the runaround and although a 1-0 loss to the Catalans was probably a fair result, Los Boquerones gave a wonderful account of themselves.
That can't be said in their performance against Getafe. Malaga were woeful.
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Such "night and day" showings could cripple their season and Gracia will be hoping that they bring their A game to the Santiago Bernabeu.
Let's take a look at three things that could shape the outcome of this one.
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So far this season, Los Blancos have hit a perfect ten goals at home in La Liga without reply.
Granada, surprisingly, have come the closest to upsetting that particular apple cart, having a perfectly legitimate goal chalked off but more than holding their own in the Spanish capital.
Their 1-0 defeat was a victory of sorts given that they had lost 9-1 to Madrid on their previous visit.
Goals win games and Rafa Benitez's expert tactical nous has ensured that all of his front players have a part to play.
Even without the pace of Gareth Bale, Real are well set with players who know where the target is.
Isco, Malaga's boy wonder
Isco gets a chance to put one over the team where he made his name.
Under Manuel Pellegrini's tutelage, the youngster played a full part in Malaga's assault on the Champions League and won himself a "Golden Boy" - the youth Ballon D'Or - in the process.
Since his transfer to Madrid he hasn't had too much of a chance to express himself in the way in which he would like, suffice to say that this season and last, he has only played when James Rodriguez has been injured.
Standing ovations after almost every performance in 2014/15 hints at how well respected the player is amongst the Los Blancos fan base and Isco continues to please.
Malaga may well be rueing the day they let him leave if he turns in another polished 90 minutes in this one.
Goals, what goals?
It's quite obvious where Malaga's problems lie.
Their first four games of the season saw them fail to trouble the opposition goal. Not a single goal scored.
Duje Cop, a new signing, has been a big disappointment and has already found himself on the substitutes bench. Not a good sign for player and club.
Charles, a big name signing from Celta Vigo was unlucky to have a late goal chalked off for offside in the first match of the season against Sevilla, but in reality that's as close as anyone has come to breaking the duck.
Quite clearly not good enough at this level.
Up against a team that didn't concede in their first four, Malaga absolutely have their work cut out.