Isco is still 20 years old. But he should join a bigger team next summer if he keeps playing like he has in this edition of the UEFA Champions League. He joined Málaga at the start of the 2011-2012 season after the Andalusian team payed the 6M€ clause that tied him to Valencia. Isco is a playmaker that is able to score, dribble and pass the ball. This is arguably Málaga's best player already.
Pellegrini's team is currently ranked fourth in La Liga BBVA and just five points behind Mourinho's Real Madrid. It's true that they're tied with Betis, but Málaga should not have a problem in finishing La Liga in that position and therefore qualify to the Champions League for the second season in a row.
Luckily enough for Real Madrid, defensive midfielder Jérémy Toulalan will not be available to play. He's one of the best defensive midfielders in the game and how other bigger markets slept on him while he was leaving Lyon still amazes some football analysts. With Toulalan's absence, Iturra and Ignacio Camacho will likely play on the midfield, but Pellegrini could also choose to play with a three-man midfield and place Demichelis there to stop Real Madrid's playmakers.
Málaga's defensive line isn't great. Monreal, Welington, Jesús Gámez and Demichelis are the team's starters whenever the Argentinian player doesn't move to the midfield position. Whilst they aren't great, they do have a great goalkeeper to clean up their mistakes. Argentinian Willy Caballero is an amazing goalkeeper with agility and energy. He doesn't have the classic body of a goalkeeper, but he jumps high and is able to reach for some complicated balls that would go in against other keepers.
Upfront, former Valencia winger Joaquín provides some creativity. He pairs with Isco and Eliseu when Pellegrini plays with a 4-2-3-1 formation. Eliseu brings a lot of energy and is able of shooting the ball from the outside. The Portuguese player is also dangerous off set pieces because of his brilliant left foot, so that could harm Real Madrid's defense a lot.
Javier Saviola is the team's striker. He never succeeded in Barcelona, Madrid or Benfica, but he's having a good season so far in Málaga. He's the team highest scorer with five goals so far, but Málaga is a team in which any given player is able to score.
Buonanotte, Juanmi and Portillo will likely be on the bench waiting for Manuel Pellegrini to give them a chance if the game isn't going well.
Málaga surely has the quality to be a threat for Real Madrid, so the players better be ready.