Lionel Messi couldn’t have asked for a more dramatic way to score his 500th goal for Barcelona.Barca desperately needed to beat Real Madrid to stand a chance of winning La Liga this season and that looked unlikely heading into injury-time.James Rodriguez’s 85th-minute equaliser appeared to have earned Los Blancos a point, drawing the scores level at 2-2.But the visiting side had other ideas.Marcelo failed to stop Sergi Roberto’s surging run, who offloaded the ball to Andre Gomes. The substitute slipped in Jordi Alba, whose pull-back fell perfectly to Messi.It was never in doubt as soon as the ball reached the Argentine as he swept it past Keylor Navas to win the match for his side.But how would he celebrate scoring what could one of the most important goals of his career - not to mention his 500th for the club?By going over to the Madrid fans and holding up his ‘Messi 10’ shirt in front of them, of course.

It was an epic celebration that matched the occasion.

But why did Messi do it?

Well, Spanish outlet Sport have explained exactly why.

They explain how Messi was frustrated with a number of incidents during the match and his celebration was a case of all of that pent-up frustration.

"Messi was angry with how things had gone on the pitch," the report says.

"Casemiro's yellow card, Marcelo's elbow, which brought blood from his mouth, Casemiro's consistent fouling, Sergio Ramos' red card, James Rodriguez's late equaliser... A series of events that had fired up Messi. 

"The goal in the 92nd minute, then, produced an explosion of the anger which had been build up and the best possible revenge for it: an added-time winner against Barça's eternal rival, taking the Blaugrana to the top of the table. And that was why, without having thought about it, after the celebration with his team-mates he held his shirt aloft in front of the Bernabeu stands to demonstrate what he had been capable of doing."

Some may have claimed that this unique celebration was because he had reached a remarkable milestone. But Sport disagree. They suggest he was simply reminding Madridistas that he was still one of the greatest players in world football - having just scored a brace to beat them.

"There were some who felt it was a demonstration that his contract renewal is close to completion, that the kiss on the badge was the prelude to signing an extension (it could yet be), that it was because he'd reached 500 Barça goals," Sport wrote.

"It was none of that. It was just the sensation of coming through so many obstacles and beating Madrid in the best way possible. That was why he showed his shirt to the Madrid fans: an unmistakable sign that someone special had just passed through the Bernabeu."

So there you go. It wasn’t a planned celebration. It wasn’t because he had just reached 500 goals, it was simply a spur of the moment reaction to scoring such an important goal in a game where so many things had angered him.