El Clasico: Barcelona and Real Madrid's key players on Sunday

Ahead of Sunday’s El Clasico, Sky Sports’ Scott Minto picks out five key players who could swing the game in the favour of Real Madrid or Barcelona.

Lionel Messi

Problems with Luis Enrique seem to have gone (or at least put to one side) and Messi remains the man who makes Barca tick either by scoring, assisting or just controlling the game. The sensational Argentina international has nine goals and two assists in his last five La Liga appearances. Barca have a great chance of the treble if Messi – and his front-three colleagues Luis Suarez and Neymar - keep up their current form until June.

Messi is the key man in this fixture. He was quiet in the last Clasico, when Real ran out 3-1 winners, but, along with Suarez and Neymar, he’s in great form. That trio enjoy each other’s company both on and off the pitch, and if they click on Sunday they could cause Carlo Ancelotti’s men real problems.

Cristiano Ronaldo

Ronaldo is not at the level he was at earlier in the season – when he scored a total of 21 goals in 13 consecutive games – but that was impossible to keep up. He’s still far from his usual standards, though, and is becoming frustrated because of it.

He’s not unhappy or annoyed with Gareth Bale as some suggest, but a lack of celebration with Bale's goals against Levante shows that, for him to be happy, not only does he need the team to win, but he also needs to be the main man. He’s still key for Real Madrid though. If he performs, they have a great chance. 

Luka Modric

Modric made his first start since November against Levante, so he’s not fully fit – but he does give Real Madrid an extra playmaker to take the pressure off Isco. Real look so much more balanced both defensively and offensively with him in the side. Modric is able to take the pressure off the defenders by keeping the ball better than others while having great creativity for the forwards.

Javier Mascherano.

Barcelona’s front three is the best forward line in the world but the team can be vulnerable to the counter attack. Mascherano, along with the two centre backs, Gerard Pique and Jeremy Mathieu, is the player who has to stop the counters as Real Madrid probably have the paciest attack around. Mascherano is filling that holding role in the absence of Sergio Busquets. He’s not as good on the ball, but better defensively.

Iker Casillas

Casillas had a really poor game against Schalke, was 'rested' against Levante (wrongly in my opinion) and had his name whistled in the warm up for that match. The Real Madrid captain has not consistently been at the level he used to be. Real need him to be at his very best for this game because on his day, he's still unbeatable. But if he plays like he did in the Schalke game, Madrid will need to score three.

Watch Barcelona v Real Madrid live on Sky Sports 5 HD from 7.30pm on Sunday