Before Saturday's El Clasico at the Bernaebu, a lot of the narrative centred - as it always does - on Lionel Messi and Cristiano Ronaldo.The two finest players in world football were set to go head-to-head yet again, with Ronaldo's side in desperate need of three points to stay in the La Liga title race.Before the game, football fans were pretty surprised with Zinedine Zidane including Matteo Kovacic in his starting XI in place of Isco.Gareth Bale was on the bench surprisingly, with the Croatian midfielder tasked with providing more midfield security.In the first-half, he did just that, with Barca creating very little but in the second period, the former Inter Milan man made a very costly error for the first goal.As Ivan Rakitic burst through the midfield, Kovacic could have gone to tackle him.Instead, he and Casemiro were too occupied with shackling Messi and instead, Barca cut through them, with Sergi Roberto teeing up Luis Suarez for an easy finish.Just watch below and notice Kovacic checking on Messi.

VIDEO: BARCA'S FIRST GOAL

Real's Messi obsession really cost them.

Football fans on Twitter noticed their error and were quick to judge Los Blancos for their naivety.

FOOTBALL FANS REACT

Zidane will have learned his lesson.

Barca made the Frenchman pay shortly after as Messi fired in a penalty to make it 2-0 and effectively seal the victory for Valverde's men.

Dani Carvajal was also shown a red card in the build-up to the second goal for a very deliberate handball.

Remember when Barca were said to be in a crisis?