Stark center of attention for Madrid-Barca

Real Madrid face Barcelona for the third time in two weeks on Wednesday, this time with a berth in the Champions League final on the line. The first leg of the Champions League semifinal kicks off live on FX with coverage beginning at 2 p.m. ET. It's an epic clash between the two biggest rivals in all of sport and one that features a flat-out star match between Cristiano Ronaldo and Lionel Messi.

Jose Mourinho's Real Madrid enter the game with a slight edge. While La Liga is out of their reach, they are not the team that was humiliated 5-0 at Camp Nou earlier this season. Instead, they are the reigning Copa Del Rey champions, having shut down Barcelona last week to win in added time behind Ronaldo. They are also unbeaten in two straight against their arch-rivals and have shown that they can shut down what many believe is one of the greatest teams of all-time.

But Pep Guardiola's men cannot feel too cowed. With Messi, Andres Iniesta and Xavi forming the heart of the best-passing and deadliest attack in all of soccer, the Catalans know that if they can play their game on the day, they can beat anyone. But while the accolades keep coming - Messi reached another milestone on the weekend, scoring his 50th goal in all competitions - the signs of strain are also starting to show.

Barcelona have been runaway league leaders all season long and have been the favorites to win the Champions League since August. But after 24 straight months of high-level play, and with the bulk of Barcelona's starters also forming the nucleus of Spain's World Cup winning side, the passes are no longer as crisp, and the attempts on goal no longer rain in as frequently. Barcelona of course are almost certain to win their third straight La Liga title - and their 21st overall - but the club's overwhelming focus is and always has been on European glory.

And who kept them from their fourth European Cup last year? None other than Mourinho, who surprised everyone by leading Inter Milan to the title by routing Barcelona at this same stage with a first-half blitz the Spaniards never recovered from. In that game, Inter used constant pressure, forcing turnovers and running Diego Milito right down their gut to rattle Barcelona. You can bet that Mourinho, this time using Xabi Alonso and Mesut Ozil, will attempt to pull off the same trick.

Mourinho's team showed last week that if they get tight on Barcelona's midfielders and use any means fair or foul to dispossess them, Barcelona's advantages evaporate. But the question is whether or not Madrid will get to use those aggressive tactics. The man in the middle at the Bernabeu is German ref Wolfgang Stark, an official known as a stickler with a some controversy in his past. Stark has been criticized for handing out too many cards and disrupting the flow of high-profile matches, and in one notorious incident, had to be escorted off the field by Canadian police after a stormy U-20 World Cup semifinal that ended up with members of the Chilean team being maced by the cops.

Real Madrid have two key absentees: out for the first leg are Sami Khedira (thigh) and critical stopper Ricardo Carvalho (suspended), two men who were instrumental in smothering Barcelona in the Copa Del Rey. Carvalho's loss is massive. He is one of the best and most overlooked defensive players in the game, possessing an unerring sense of positioning that frustrates his opponents. He's also willing to do the dirty work and make the tough tackles.

Real Madrid also cannot be too wild: Key playmaker Ronaldo is one card away from missing the second leg as are Angel Di Maria, Sergio Ramos and Raul Albiol. The loss of Ronaldo, Madrid's bona-fide match-winner, would be a crushing burden in a second leg.

But Barcelona's defense is a bit shaky: Dani Alves has been a pressure point all season long, largely because he is over-willing to range forward, allowing a great deal of room behind him that opponents can occupy. Eric Abidal (liver tumor) is also out and Adriano and Maxwell are both injured, leaving them shorthanded on the left flank. Carlos Puyol is still doubtful and Javier Mascherano has not been adequate as cover.

Barcelona also may be missing a key midfielder. Newspaper reports in Spain say that Iniesta is a question mark after he picked up a knock against Osasuna on the weekend.

There's really no clear edge in what is the marquee match-up of this round. Until last Wednesday, Real Madrid had failed to beat Barcelona in six attempts. But, at this same stage, Real Madrid have brushed aside Barcelona twice, en route to their crowns in 1959-60 and 2001-2002, and in six European games have won three and lost once. History also gives the Special One a nod: he KO'ed Barcelona twice in three attempts with Chelsea and once with Inter.

Jamie Trecker is a senior writer for FoxSoccer.com covering the UEFA Champions League and the Barclay's Premier League.