There are many factors that can decide any Clasico, from magical moments from special players to tactical manoeuvres that can change the course of a game.
Wednesday's matchup between Barcelona and Real Madrid will be no different and it may well be influenced by any of the following factors.
Will Valverde follow Messi?
Casemiro will return in holding midfield for Real Madrid, which gives Fede Valverde a licence to roam around the rest of the pitch.
It's unknown which role Zinedine Zidane will give the Uruguayan at the Camp Nou, but he might be persuaded to use the youngster to keep tabs on Lionel Messi.
Zidane has used Mateo Kovacic in that role before and the Croatian did well until one mistake cost his team.
However, Zidane's trust in Valverde is total and he could assign him to do the job.
Who will have more possession?
Every Clasico in the last decade has followed a similar pattern as Barcelona have had more of the ball than Real Madrid, and this season's statistics suggest that history could repeat itself on Wednesday.
The Catalan side have had the highest average possession with 64.1 percent, while Los Blancos sit on an average of 58.5 percent.
On the other hand, Real Madrid have seen much more of the ball in recent weeks and it has brought them results.
Meanwhile, Barcelona are showing they're capable of playing differently to the tactics that Pep Guardiola installed.
Will the defenders be at their best?
Sergio Ramos and Gerard Pique have been the staples of their teams' respective defences over the past decade, but that doesn't prevent criticism coming their way.
Their performances are under the microscope, although their teammates aren't innocent either.
There's no room for mistakes in a Clasico and a major error could cost someone the game.
Which player will blur the lines?
Both coaches will enjoy pitting their wits in this tactical battle as they look to gain an advantage on each other.
They will use players like Antoine Griezmann or Isco to destabilise the opposition and to pick the locks of their defences.
Griezmann could play on the shoulders of Casemiro or Dani Carvajal, breaking between the lines to good effect.
For the visitors, Isco could do the same job, creating confusion amongst Frenkie de Jong and Sergio Busquets.
Will there be an unlikely hero?
The Clasicos of the next decade will feature the likes of Ansu Fati, Rodrygo and Vinicius, but one of them could spring a youthful surprise and decide the final matchup of the 2010s.
They're all expected to start on the bench, but they'll all hope to make a difference at some point during the encounter.