Just how good a footballer for Real Madrid and Barcelona are can depend on how they perform in El Clasico. Many players have excelled in the high pressure environment, whereas others have been cast aside after a poor performance in football's greatest match up.
To succeed in El Clasico you need to be one of the top players in the world - to be merely a good player won't cut it - as many have discovered over the years. Let's take a look at those who have succeeded and those who have failed in the biggest game in club football.
Lionel Messi has the most goals and assists in El Clasico history, so it's fair to say he's enjoyed a bit of success in the fixture. After bursting onto the scene with a hat-trick against the Catalan's main rivals in 2007, the little Argentine hasn't looked back.
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Time after time he has humiliated some of the best defenders in world football and proved that he is the best player the game has ever seen. It's unlikely anyone will top his remarkable El Clasico record.
It would seem wrong to mention Messi without mentioning Cristiano Ronaldo. After a slow start to his El Clasico career, the Portuguese star has hit form in the fixture - his six game scoring streak was the peak of his career against the Catalans.
He is always Madrid's biggest threat whenever Spain's biggest two clubs collide; the entire Barcelona back-line will be glad to see the back of him if Ronaldo ends up moving at the end of the season.
Pedro was one of El Clasico's most underrated players; the fans didn't get as excited about him as they perhaps should have done, especially considering his impressive goals record. The winger has five goals against Real Madrid - some of them proving to be pivotal.
He scored what turned out to be the title clinching goal when Barcelona beat Real Madrid 2-0 at the Bernabeu in 2010, as well as netting in the 2011 Champions League semi final between the two clubs. Real Madrid will have been among the most relieved to see him leave for Chelsea last summer.
Who's struggled in El Clasico
Sergio Ramos will likely go down as one of the all time great Real Madrid players - that will be in spite of his El Clasico performances, not because of them. Despite scoring a few goals in the fixture, Ramos has been at fault for several Barcelona goals over the years.
In his defence he has come up against some of the game's all time greats, but that excuse won't wash with the capital side's most loyal supporters. A montage of Messi's battle against Sergio Ramos wouldn't make comfortable watching for the Madrid captain.
There was a lot expected of Barcelona's prodigal son when he returned to Catalonia in 2011 - he didn't quite live up to the hype. Despite scoring and assisting a relatively high amount of goals, Fabregas always looked one step behind his teammates. That became painfully evident in El Clasico matches.
It's rumoured that Real Madrid's entire tactical plan changed when they discovered that Fabregas was going to replace the injured Andres Iniesta when the two sides met in 2012. Madrid felt that Fabregas didn't retain the ball as well as Iniesta and they were proved right - they pressed him all game and the result was a rare dominant display from Los Blancos. Fabregas hasn't looked the same player since that game.
There was a theory around Spain's capital that when playing in El Clasico, Xabi Alonso was a luxury Real Madrid couldn't afford. His ability on the ball was restricted due to Barca's high pressing and he was often found wanting defensively.
Alonso didn't do a lot to diminish those theories.
It seemed that Messi and Iniesta relished the thought of coming up against him, judging by the myriad of times they effortlessly dribbled past him. After Barca negated Alonso's primary skill of long range passing, they realised he didn't offer much else.
Who has been the best player in recent times in El Clasico? Give YOUR opinion in the comment box below!