Lionel Messi scored his 500th goal in Barcelona colours with a dramatic injury-time winner in this evening's meeting with Real Madrid, helping his side to a 3-2 win that takes them to the top of La Liga.

In a thrilling El Clasico encounter with numerous twists and turns, Madrid squandered the lead and then battled back with 10 men, only for Messi to pop up with a landmark goal with the final act of the match.

With the dust settled on the five-goal thriller, Barca move level on points with their rivals, who have a game in hand to play, but take top spot by virtue of a now-superior head-to-head record - Messi's second goal of the night blowing the title race wide open.

Madrid felt that they should have had a penalty with less than three minutes on the clock after Samuel Umtiti clumsily caught Cristiano Ronaldo's leg, but referee Alejandro Jose Hernandez decided against pointing to the spot.

The hosts completely dominated the early stages of the match, with Ronaldo and Karim Benzema both forcing saves out of opposition keeper Marc-Andre ter Stegen.

Barcelona had a couple of half-chances of their own, the best of which saw Luis Suarez send a shot flying past Keylor Navas's goal from the edge of the box, having also blasted over on the volley.

The breakthrough arrived just short of the half-hour mark through one of the more unlikely sources, as Casemiro was in the right place at the right time to tap the ball over the line after Sergio Ramos's initial attempt hit the post and rolled across goal.

It took just four minutes for Barca to level things up, however, thanks to a piece of individual brilliance from Messi, who weaved past a couple of players and picked his spot for his first El Clasico goal in seven outings.

By ending that three-year drought without a goal against Real, the Argentine also edged ahead of Madrid great Alfredo Di Stefano as the top scorer in this fixture with 15 to his name.

Ter Stegen was required once again soon after to keep out a bullet attempt from Luka Modric, moments before Gareth Bale hobbled off with another muscular problem to be replaced by nine-goal midfielder Marco Asensio.

There was a contentious decision late in the opening 45 minutes, as the already-booked Casemiro dodged a second yellow for a cynical block on Messi, while the little maestro somehow failed to convert from close range from the final kick.

Much like in the first half, it was the hosts who came out the quicker at the start of the second as Toni Kroos produced another top save out of a busy Ter Stegen.

Benzema nodded a Marcelo cross at Ter Stegen and Paco Alcacer, preferred to Arda Turan in the forward line in Neymar's absence, saw his poked effort kept out as the chances continued to arrive at both ends.

Gerard Pique was the next to come close, being denied by Navas from a bullet header, and an end-to-end spell then saw Ronaldo fail to convert from seven yards out once Asensio squared the ball to him, before Suarez blasted at Navas near the back post.

A huge moment in the match, and indeed the title race, then arrived 17 minutes from time through Ivan Rakitic's curled effort past the reach of Navas - his ninth goal of the season.

Another twist was to follow as the final 10 minutes approached when Ramos lunged in on Messi two-footed for a 22nd career red card, but Pique's failure to convert when one-on-one moments later ensured that the match remained in the balance late on.

A dramatic Rodriguez goal in the 85th minute looked to be enough to keep Madrid at the summit, making a simple front-post run and firing into the roof of the net, but after being picked out on the edge of the box Messi swept home to conclude one of the most memorable tussles between the heavyweight sides.