Sunday's El Clasico could already be a decisive factor in where the La Liga trophy ends up in May.

Barcelona are currently four points ahead of Real Madrid in the table and a win at the Nou Camp would put them in the driving seat to win the title once again.

However, the Blaugrana will have to try and beat their bitter rivals without the leadership and quality of Lionel Messi.

The Argentine picked up a nasty arm injury in the 4-2 win over Sevilla and is likely to be absent until after the next international break.

It means that El Clasico will not have either Messi or Cristiano Ronaldo featuring for the first time since 2007.

That time, Real claimed a 1-0 win at the Nou Camp thanks to a goal from Julio Baptista.

In the build-up to Sunday's game, Ronaldo's absence has been discussed just as much as Messi's.

The Portuguese moved to Juventus in the summer and Real's form and ability to score goals have seriously dipped since his departure.

And Barca legend Carles Puyol believes that Los Blancos must have seen this coming as they were so heavily reliant on the 33-year-old goal machine.

"When the best player leaves, it's logical that the team gets worse," Puyol said."They have to look for solutions, another way of playing, they relied heavily on Cristiano's goals.

"Now they have to replace those goals with other players scoring, other styles of play. They [Barcelona] have to play their football, keep the ball and try to take advantage of the chances they have to score.

"Their style is very clear."

Maybe Real will have to completely alter their style.

For nine years, the team was focused on getting the ball to Ronaldo and creating as many chances for him as possible.

Now, they're trying to play the same but without that focal point and it's simply not working.

Over to you, Julen Lopetegui.