A European knock-out stage tie between Manchester United and Real Madrid -- the biggest football clubs in Britain and Spain, respectively -- is understandly a highly anticipated and grand occasion. It could also be a fascinating tactical clash as well. The two men leading the clubs into battle -- Sir Alex Ferguson for United and Jose Mourinho for Madrid -- both have keen tactical minds and they are quite familiar with each other. Each are also stocked with tremendous squads.

Typically, Madrid are deployed in a 4-2-3-1 shape. At their best, the Spanish side's front four tenaciously press the opposition's backline while their two central-midfielders close down their counterparts as well. When the ball is won -- preferably high up the pitch -- they break at incredible speeds and quite often, they pour in the goals. El Clasico is always a spectacle because of Madrid's great rivalry with FC Barcelona. In recent years though, these contests have arguably reached new heights and much of this is due to the Catalan's possession-based style being a sharp contrast to the capital side's quick transitions into space -- this is a match made in heaven for entertaining football.

The first name on the team sheet for Madrid is the brilliant Cristiano Ronaldo (unless Mourinho happens to write the names down alphabetically -- in that case, it's Alvaro Arbeola). The former United superstar -- whom Gary Neville believes is the most extrordinary player the Premier League has ever seen -- is the talisman for Madrid and he pretty much has the freedom to do whatever he wants in attack. The Portuguese attacker is positionally based high up the pitch on the inside left, however, he'll often wander to the middle or to the right hunting for vulnerabilities in the opposition's shape or personnel. If there's an obvious weakness, the former Ballon d'Or recipient will exploit it.

On the ball, Ronaldo is nearly unplayable. His incredible acceleration, mesmeric dribbling, strength, and imagination are just some of the ingredients that make him a force on his raids towards goal. His searing pace and heading ability also make him a danger to get on the end of any pass. United's right-back -- Rafael -- has the challenge of his professional life during this two-legged tie.

Madrid are undoubtedly built around Ronaldo, but they also have a plethora of other dangerous attackers. Up front, the lone striker on Wednesday will either be Karim Benzema or Gonzalo Higuain. The Frenchman was actually once thought to be a transfer target for United. The 25-year-old is a well-rounded striker as his technical ability allows him to drop deep or to move out wide in order to link play. He's a decent finisher as well -- albeit somewhat inconsistent with this -- and his strength and speed assist him in getting into goalscoring positions. He isn't in the greatest form at the moment though. Higuain, who's more of a poacher and a better finisher -- but has less of an all-around game than Benzema -- may get the nod on Wednesday. The Argentine's main movements are runs into the channels or getting into the box for chances.

The squad's main playmaker is the delightful Mesut Ozil. The German international is a can-opener as his impressive close-control, awareness, and improvisation allows him to skip into space where his left-boot is a constant supply of chances for his teammates. Ozil tends to position himself behind the opposition's holding-midfielders and when possession is won, he looks to receive the ball between the lines -- this can be in a central position or out wide and away from his natural foils. When he drifts to the left, he'll often combine with Ronaldo or play a penetrating through-ball for one of his fellow attackers. When he drifts right, he'll often occupy the vacated space created by Angel di Maria's darting inward runs. From near the right flank, Ozil will look to drill in a cross for Ronaldo at the far-post or he'll roll a diagonal ball into the box for any attacker willing to make a clever run.

An alternative to Ozil is former Tottenham Hotspur midfielder Luka Modric. The Croatian began his career as a No.10 but his time in England turned him into a tempo-setting central-midfielder. Since his arrival at the Bernabeu, he's often been asked to play a role that is somewhat in between the two. If Modric is on the pitch in place of Ozil -- or when the German is shunted out wide -- he tends to be more of a proper central-midfielder as he positions himself deeper. Madrid's shape then turns more into 4-3-3 from a 4-2-3-1. If Ozil struggles in linking the midfield and attack, Modric is an option to receive the ball in deeper positions so that he can carry the ball forward. The former Spurs man is also a more patient option to break down deep-defending sides.

On the right-flank, the first-choice attacker is di Maria. The Argentine is a bit hit-or-miss in attack on any given day, but he does typically offer industry and a willingness to defend. He plays much deeper than Ronaldo does on the left. When di Maria receives the ball, he'll look to cut in onto his stronger left-foot and during these diagonal forays, he often looks to play a ball over the top for Ronaldo or a through-ball into the channels for one of his fellow attackers. Jose Callejon is an alternative that offers more natural width, but his defensive ability isn't on par with di Maria's.

In Madrid's double-pivot, former Liverpool midfielder Xabi Alonso is the deep-lying playmaker while German international Sami Khedira is the driving and energetic force. The former's range of passing is possibly only rivaled by the likes of Andrea Pirlo and Paul Scholes. The Spaniard tends to drop deep to receive -- sometimes in between Madrid's central-defenders -- and from here, he seeks to spray a ball out wide to the flanks or into the channels for an attacker to run onto -- particularly Ronaldo. According Borussia Dortmund manager Jurgen Klopp -- whose side got the better of Madrid in the Champions League's group-stages -- the key to containing Madrid is to nullify Alonso:

"Our plan was to take Xabi Alonso out of the game. If Alonso plays the way he can play, it's almost impossible to defend against Real Madrid. Once we put [Mario] Götze on him we knew that, if our two full-backs were very mobile, we would have the advantage over Ronaldo. If you block Xabi Alonso it means Pepe always has the ball – and that's a very different thing." - Klopp

Khedira is a key figure as well. His combativeness is important in screening for the less mobile Alonso while his energy allows him to burst forward and through the opposition's midfield. The German is also excellent at pressing. He's not as technically gifted as Alonso, Ozil, nor Ronaldo but he's responsible enough on the ball.

The expected back four for Wednesday is Alvaro Arbeola (right-back), Fabio Coentrao (left-back), Sergio Ramos (center-back), and Raphael Verane (center-back). The contentious Pepe has just returned from injury so this tie may have come just a bit too soon for him to feature. Marcelo -- who's generally first-choice at left-back -- has also missed quite a bit of time recently due to injury when he was apparently on the Anderson diet.

Coentrao is a more responsible defender than Marcelo but he doesn't link up as well with Ronaldo in attack. Nonetheless, with the aggressive positions the talisman tends to take in attack, his compatriot -- Coentrao -- might offer better balance to Madrid's left-side.

Arbeola is a solid right-back but he offers more defensively than he does in attack. He's a bit like Manchester City's Gael Clichy in that he tends to get tight to the man he's marking. The Spaniard will either try to cut out any passes to his opponent or he'll look to immediately get stuck in when that player receives. Going forward, he's decent enough but not so much that teams sometimes don't dare him forward. Part of this is because he plays for immensely talented teams in Madrid and in Spain so he's logically deemed the least dangerous player. During the past summer in Euro 2012, Arbeola was intentionally given space to get forward into by some of Spain's opponents.

In central-defense, Ramos is strong aerially and he's willing to step out of the back. Varane, projected to start over Pepe, is a talented 19-year-old that compliments Ramos well with his willingness to sweep in behind. The Frenchman has been impressive as of late -- particularly against Barcelona a few weeks ago during Copa del Rey tie -- as he's shown tremendous pace, positional awareness, tackling ability, and proficiency on the ball. The youngster was wanted by Ferguson prior to his move to Madrid.

Club and Spain national team legend Iker Casillas is unavailable due to a broken hand - in steps Diego Lopez. The former Villarreal and Sevilla goalkeeper is a presence at 6'5" and as you might suspect, he generally deals well with crosses. He's a solid shot-stopper too and he's competent with his feet. He does, though, tend to stick to his line more than Casillas. Lopez appears to have been an astute pick-up by Madrid just prior to the January transfer window closing.

Despite Madrid's disappointment in La Liga this season, their displays in the past month indicate that they're nearing top form. Their tenacious pressing and lightning quick counters should be very worrisome for United. There is a growing school of thought, though, on how to play against Mourinho's side -- give them the ball. Here's what Real Betis manager Felipe Mel had to say after defeating Madrid in December -- this sentiment appears to be increasingly shared by other sides in Spain as well:

"Against this Madrid you have the ball and you think that you're dominating. Suddenly, wallop. In three plays they have created six chances. They play openly on the break and it works well for them. They have no problem doing that because they know that when they do that they are the best. We tried to let them have the ball." - Mel

Essentially, the idea is to deny them space to break into. Inviting pressure has it's obvious fallacies but keeping the shape tight and compact limits space between the lines and into the channels for Madrid's attacker to operate in. It can also create space to break into when possession is won.

A reasonable goal for United is to leave Spain with a scoreline no worse than a one-goal deficit. A level result or one with a lead would be likely leave the English side feeling that they have the advantage for the return leg at Old Trafford. Therefore, it wouldn't be surprising to see United take a cautious approach at the Bernabeu. With all of this in mind, what tactics might Ferguson use at the Bernabeu?

There seems to be two obvious possibilities: (1) A counterattacking 4-4-1-1 system where United keep their shape compact and then look to break down the flanks -- particularly down the right where Madrid's left-side could be vulnerable against quick transitions due to Ronaldo's bold positioning -- or (2) a lopsided shape where Phil Jones provides inside cover against Ronaldo from a right-sided central-midfield role. There would be some concern with either tactic though.

For the counterattacking 4-4-1-1 system, there's the simple worry that neither United right-winger -- Antonio Valencia nor Nani -- are in good form at the moment, despite some encouraging performances as of late. In addition, if a double-pivot of Michael Carrick being partnered by either Tom Cleverley or Anderson is used, they might not provide enough bite to combat Ozil, the inward movements of di Maria and Ronaldo, nor Khedira's surging runs. United could potentially run into the nightmare scenario where they're overrun and don't have an effective outlet to relieve pressure.

If Jones is used to bracket Ronaldo in support of Rafael, then this will certainly have repercussions elsewhere on the pitch. Carrick, Jones' likely partner in this scenario, could be left to defend in too much space if his partner is sucked too far wide and/or too deep while paying attention to Ronaldo. In order to assist Carrick, United's left-sided attacker might need to tuck in and be an auxiliary central-midfielder while the player playing in support of Robin van Perise would need to be disciplined and stay goalside of Alonso. This all could result in a situation where Arbeola is given space to get forward into because of a possible lopsided United shape. This may or may not be a scenario Ferguson is willing to gamble on.

Other less likely possibilities are a diamond midfield or a 4-3-3 (4-1-4-1 when out of possession). The former shape might actually make decent sense because crowding the middle and daring Madrid's full-backs forward could be deemed as the lesser of all possible dangers. However, this would leave United without an outlet to relieve pressure when they try to counter. In a 4-1-4-1 shape, the lone holding-player -- likely Carrick in this hypothetical scenario -- would have too much lateral space to cover when Madrid have the ball. In turn, this would leave space for exploitation in front of United's back four.

For Madrid, it's pretty simple -- they're likely to be deployed in their 4-2-3-1 shape while a 4-3-3 with Modric might be a Plan B if they struggle to break down a possible deep-defending United side. An alternative Plan B would be to use Higuain and Benzema together in a 4-4-2/4-2-4ish shape if Madrid are in need of a goal. The two strikers, though, have only been deployed together five times this season.

The unknown is Ferguson's tactics. There's also a wide range of possibilities with his selections choices as only van Persie, Carrick, Wayne Rooney, Rio Ferdinand, David de Gea, and Patrice Evra seem certain to start. Maybe Rafael as well. It should be fascinating to see what the Scotsman decides to do because it'll likely be the major influence on the pattern of Wednesday's game. Will the United manager get it right against one of the few clubs and managers that he hasn't gotten the better off during his legendary career?



