It's here! Real Madrid and Barcelona lock horns in the first of four El Clasico encounters in 16 days as the great rivals meet in their La Liga clash at the Santiago Bernabeu.

PENALTY!! Villa goes thorugh and Raul Albiol gets his arm around the striker's neck and hauls him down! Real down to 10 men! Messi, who has never scored against a Mourinho team, will take the penalty...

Ronaldo's fizzing effort dips and swerves and hits the foot of the post! Valdes was scrambling to get across, that would have been in!

Ronaldo 'wins' a free-kick within sight of goal. That was pretty cheap, but he has a sight of goal from this dead ball. The crowd clap is expectation...

Di Maria brings down Alves as Ozil goes for a jog down the touchline.

The last time a match between these two ended 0-0 was in November 2002 at the Camp Nou.

The second half is underway! Surely this can't end goalless - can it?

More from OptaJose: "HT Stats - Shots: 8-3, On target 4-3, Fouls: 13-6, Passes: 116-383, % successful 68%-91%, Dribbles 12-14, % successful 33%-43%"

The whistle goes for half-time, and this match is nicely poised for the second half.

So close for Real! Sergio Ramos heads a corner back across goal and Ronaldo's header is cleared off the line by Alves! How did that stay out? Valdes was floundering there!

That was the first bit of Messi magic we have seen in thios match. Mourinho's tactics have helped keep him relatively quiet thus far. Messi has never scored against a Mourinho team in 11 previous meetings.

Wonderful move, the best of the game so far! Messi plays a one-two with Villa and runs across the edge of the box to meet it before forcing Casillas to beat his shot away!

Messi's head met Alonso's unwitting boot as he stumbled and fell to the ground. No foul, and the ball is given back to Real for the match to continue.

Now Messi has gone down clutching his head after colliding with Alonso. The ball is kicked out of play for the World Player of the Year.

Villa goes for an ambitious curling effort from range but bends it right at Casillas.

Busquets goes down after being challenged by Marcelo and Pepe, but writhes around as though he has been assaulted with a crowbar! He is a vital yet underrated component of both the Barca and Spain teams, but he doesn't win many fans because of behaviour just like that.

Barcelona have scored more goals from outside the penalty area in the league this season than any other side with 14, more than double Madrid's six. (Opta)

Pique has to time his jump right as he leaps to head away Khedira's ball over the top bound for Ronaldo.

Adriano runs at Sergio Ramos but tries to be too clever and falls off balance! Still, just the 500 million or so watching this game around the world saw that!

Ronaldo is put clean through and goes to pull the trigger... Adriano slides in with a well-timed tackle! The ball rebounds off Pique and Valdes gratefully gathers!

Real have numbers forward but a handful of strikes from the edge of the box are easily blocked.

Messi has scored (seven) or assisted (four) 11 of Barcelona's 20 goals against Real Madrid in the last five seasons. (Opta)