Cristiano Ronaldo scored many famous goals during his glittering nine-year spell with Real Madrid, but his winner against Barcelona at Camp Nou on April 21, 2012 is undoubtedly one of his most iconic.This was at the height of the legendary rivalry between Jose Mourinho’s Real Madrid and Pep Guardiola’s Barcelona. The two best club sides in world football. Ronaldo vs Lionel Messi.Sami Khedira scored the opening goal for Madrid in the 17th minute before Alexis Sanchez netted the equaliser with 20 minutes left on the clock.But Ronaldo had the last laugh that night, sealing all three points for the visitors thanks to one of the most memorable goals of his extraordinary career - followed by one of his most famous celebrations.Madrid’s No. 7 ran on to Mesut Ozil’s long-range pass before taking the ball to the side of Barça goalkeeper Victor Valdes. He then shot early, catching Valdes out in the process, and finished with aplomb from an acute angle.Co-commentator Ray Hudson screamed: “Deadly from Darth Vader! The Dark Invader they call him, this one is a death ray hit from Real Madrid’s glamour boy!”Ronaldo then produced his epic ‘calma’ celebration in front of a stunned Camp Nou.After watching Ronaldo’s celebration, Hudson added: “He tells them ‘Be quiet, I’m running this show now, baby!’”

Video: Cristiano Ronaldo's 'calma' celebration vs Barcelona

Watch the footage here:

Pure football heritage.

As you can see from this footage recorded from the stands, Ronaldo’s celebration did *not* go down well with the home fans, who reacted by shouting various insults at the Portugal international.

But it wouldn’t have bothered Ronaldo, who’d just scored his 42nd league goal of the campaign, in the slightest.

His goal allowed Real Madrid to take a giant leap towards securing their first La Liga title since 2008.

It also saw Barcelona slump to their first home defeat in 55 matches.

BARCELONA, SPAIN - APRIL 21: Pepe (C), Esteban Granero (R) Karim Benzema (L) and Sergio Ramos (2.R) of Real Madrid CF celebrate after Real beat Barcelona 2-1 during the La Liga match between FC Barcelona and Real Madrid CF at Camp Nou on April 21, 2012 in Barcelona, Spain. (Photo by Denis Doyle/Getty Images)

Pep Guardiola quit Barcelona days later

And just six days later, Guardiola sensationally announced that he was bringing an end to his remarkable four-year spell in charge of the Catalan club.

“The reason is simple: four years is enough,” he told reporters. “I’m drained and I need to fill up. The demand has been very high and a manager must be strong.”

BARCELONA, SPAIN - APRIL 27: Head coach Josep Guardiola of FC Barcelona looks down during the press conference at the Camp Nou stadium on April 27, 2012 in Barcelona, Spain. Josep Guardiola has today announced he is not renewing his contract after 4 years tenure as Head Coach of the FC Barcelona squad. (Photo by David Ramos/Getty Images)

Did Pep make his decision to walk away from Barça partly because of defeat in that Clasico?

We’ll never know for sure, but there’s every chance that it was a contributing factor.

Ronaldo and Mourinho ended the 2011-12 season as champions of Spain with a record-breaking tally of 100 points.