AS.com

On 20 December Spain's four Champions League representatives will learn who their opponents will be in the last 16 of the tournament.

The draw for the first knock out round of Europe's elite competition takes place at 11:30 CET at UEFA's headquarters in Nyon, Switzerland.

The 16 teams will be drawn in two separate pots, Pot 1 for the group winners and Pot 2 for runners up.

As runners up in Group D, Real Madrid will be drawn from Pot 2.

Tournament rules prevent them from being drawn with fellow Spanish teams in the first knout out round, meaning they could face one of five opponents: Paris Saint Germain, Schalke 04, Bayern, Juventus or Manchester United.

Barcelona, as winners of Group G, could face either Porto, Arsenal, AC Milan, Shakhtar or Galatasaray.

Málaga could face Porto, Arsenal, Celtic, Shakhtar or Galatasaray, and Valencia could face Paris Saint Germain, Schalke 04, Borussia Dortmund, Juventus or Manchester United.

Of all their potential opponents, Madrid will be keenest to avoid Bayern, who last season beat them on penalties at the semi-final stage. Madrid have a notoriously poor record in Germany, so much so that AS readers have voted Bayern and Schalke as the two teams they would most like Madrid to avoid in the next round.

Star-studded billionaires PSG could present Madrid with problems, boasting goalmachine Zlatan Ibrahimovic and Thiago Silva, one of the best centre-backs in the world. However, despite their riches, the Paris club side lack consistency in Ligue 1, where they are currently fourth and five points behind league leaders Lyon. Without doubt they have the makings of a great team, but are yet to find their identity.

Madrid have beaten Manchester United in their last two Champions League meetings, in 1999/2000 and 2002/03, and although the Red Devils have a wealth of riches up front with Robin Van Persie, Wayne Rooney, Danny Welbeck and Javier Hernández, their leaky defence would give 'Los Blancos' hope of qualifying should they be paired with them.

Juventus would not be easy opponents for Madrid either. 'The Old Lady' finished last season in Serie A without losing a game and their side contains legendary goalkeeper Gigi Buffon, ageless playmaker Andrea Pirlo and great forwards in Sebastian Giovinco, Mirko Vucinic, Fabio Quagliarella and Arturo Vidal.