Barcelona vs. Real Madrid: 6 Key Matchups to Decide El Clasico 2012

Yet another El Clasico battle looms this Saturday, the sixth such treat this season delivered to the footballing world by the two great clubs, Barcelona and Real Madrid.

In terms of the implications of the match, this one might be the most important of the season and perhaps the most important of the Pep Guardiola-Jose Mourinho era thus far.

With so many subplots in the match, let's take a moment to talk about the most important battles that might decide this match and, with it, the La Liga title.

Here are the six key matchups for Saturday's El Clasico meeting.

Pep vs. Mourinho

The tactical battle between Pep Guardiola and Jose Mourinho has been an interesting portion of the past year-and-a-half of this rivalry.

After both squads lost the first legs of their respective Champions League semifinals, the mind games may be even more important than in the past.

Both managers looked flustered in their Champions League battles this week, with Mourinho's tactics being unusually ineffective and Pep looking unusually frustrated on the touch line.

Now, it won't be hard to get their squads up for a match that could easily determine this season's La Liga champion.

However, setting up the proper team in order to get the best out of their squads is vital for this match, especially since both managers will want their players fit and available for their second legs.

In the end, though, with the tiki taka of Pep going against the genius of Mourinho, this will certainly be an interesting matchup to watch.

Lionel Messi vs. His Groin

In case you missed it yesterday, Messi may just have picked up a slight knock on the wet pitch of Stamford Bridge.

Late in the first half, the little Argentine slipped and seemed to stretch out his legs in an awkward manner.

He then proceeded to writhe on the field, clutching at his groin.

Soon afterward, he uncharacteristically gave up the ball that led to the only goal of the match.

Now, he did come back out for the second half and didn't look too bothered.

However, as anyone whose ever had a groin injury can attest to, this type of problem can linger and cause trouble at random and inopportune moments.

Do I expect Messi to have trouble?  No, not really.

However, it is something to watch for, especially because his loss could swing this match and, consequently, the upcoming Chelsea match.

Ronaldo vs. Alves/Adriano

When going up against one of the fastest and most skilled players in the world, you must find a way to defend.

Cristiano Ronaldo is clearly one of these players, and Barcelona recognizes this and marked him with multiple players.

However, the most important markers must be the full-backs.

In past matchups, Barca have had relative success (I said relative, guys) against Ronaldo with Abidal and Alves as the full-backs.

With Abidal unable to compete and Adriano becoming first choice, will they have similar success?

Or will Ronaldo run rampant on the right and bully Adriano?

Casillas vs. Valdes

Don't get me wrong: on equal ground, I see this one as a clear victory for Real's Casillas.

However, we are not on equal ground.

In all likelihood, the saves Casillas will be forced into making will be much more difficult and coming much more often than those faced by Valdes.

If Casillas plays well, he could be the difference-maker for Madrid.

Meanwhile, if Valdes plays like he did against Chelsea (letting in the one shot the Blues had on target), then the match could get awfully interesting.

Xavi/Iniesta vs. Ozil/Kaka

Each side has a couple of incredible playmakers in their midfield.

On Barcelona, the duo of Xavi and Iniesta move the ball around exquisitely, combining Xavi's insane passing prowess with Iniesta's dribbling, and find the perfect gaps for their teammates (or each other) to strike.

For Madrid, Ozil's vision and through balls have been a huge asset for Madrid; on Tuesday in Munich, he stuck with the play after Ronaldo drove a potential goal straight at Neuer and was rewarded with an away goal that may prove vital for his side.

On the other side, Kaka has never looked his old self while at Madrid; however, he has been showing hints of improvement. Since Madrid has the second leg looming, Kaka may have a healthy chunk of time against Barca to prove himself.

This will be an enthralling battle to watch as most attacks will probably run through these players, but expect an edge for the World Cup championship duo representing Barca.

Madrid vs. Referees

In the recent history of this storied rivalry, Madrid has had a tendency of being blown for an incredible amount of fouls and picking up red cards.

Now, I'm not buying into Mourinho's conspiracy theory surrounding Barcelona.

However, I think that Madrid is.

Hence, if Los Blancos start sensing that this match may not be going their way, this may turn ugly, like it did in the Spanish Supercopa.

Pepe is obviously the player to watch as it comes to this sort of play, but this is something to watch out for in the last 10 minutes if Madrid are behind.

Something like this could really prove to be a double whammy: it will have meant that Barca win (cutting the gap to one point) and, given the probable red cards that would result from such actions, that Madrid would be missing players heading into the final four Liga matches.

Oh and not to mention that such hotheadedness could be counterproductive toward their second-leg matchup with Bayern.

Of course, though, this may be a non-issue if Madrid can pick up a result.