What exactly is at stake?
The rivalry between the Catalan capital's two historically biggest clubs goes right back to the beginnings of organised football in the city, and took on a more formal basis when La Liga was established in 1928-29.
25-time La Liga winners Barcelona have often come out on top in 'derbis' over the years, but Espanyol are always eager to upset their bigger neighbours.
This season has seen the rivalry become even more pronounced as both Espanyol and teams have been battling near the top of the table in one of the most exciting La Liga title races in decades.
Defending champions Barca were always expected to contend for a trophy they have won in seven of the last ten seasons - but Espanyol have surprised many observers with some superb results and performances under new coach Joan Francesc Ferrer, better known as Rubi. So the three points should be more closely-contested this year than ever.
Two clubs, two stories
The two clubs had similar but slightly origins at the turn of the 20th century. Barça were established by Swiss student Hans Gamper, who came to be known locally as Joan Gamper, with many ex-pat players involved.
On the other side of the city, locally-born engineering student Angel Rodriguez Ruiz founded Espanyol as the team of mostly Spanish workers.
While the social and political differences between the two clubs can be overplayed, local supporters on each side can continue to see their team as a representation of all that is best about their city.
Crossing the divide
Many players have represented both sides of the divide over the decades, going right back to legendary 1930s shot-stopper Ricardo Zamora, who was born in the Catalan capital and gives his name to the award for La Liga's best goalkeeper each season.
Today's long-serving Espanyol forward Sergio Garcia came through Barça's famed La Masia academy and made 10 La Liga appearances for the club, before going on to become one of Espanyol's top players in history with 48 goals in 213 games.
Current Blaugrana coach Ernesto Valverde has the distinction of having played for and coached both clubs. Funnily enough he remains the last Espanyol boss to guide the team to a Catalan derby victory in La Liga, a 3-1 win at the club's old home in the Montjuic Olympic Stadium.
A city derby of international proportions
Barcelona are one of the biggest clubs on the planet with millions of fans in all four corners of the world. But their city rivals also have a fast-growing international profile, in particular since the club was acquired by China's Rastar Group in January 2016.
With supporter clubs from Montivideo, Uruguay to Sydney, Australia, Espanyol are one of La Liga's most historic and iconic clubs.