The Liga leaders, who also have a Copa del Rey final on the horizon, can move five points clear of second-placed Real Madrid with a win, but they come up against a side with nothing to lose on Saturday.
By virtue of the fact that they sit 10th in La Liga, there is precious little at stake for Sergio Gonzalez's charges on Saturday aside from the bragging rights.
Despite the 36-point differential between the sides, victory is anything but a foregone conclusion for Barca too, as Espanyol boast a six-game winning streak.
It has been a lukewarm season for Sergio after replacing Javier Aguirre last summer, with the Periquitos winning 11 of their 32 Liga outings so far, losing 12.
Still, given how close they came to relegation last season under Aguirre, whose side ultimately finished three points above the drop zone, the Espanyol fans will be pleased that there is nothing left to play for this time around.
Despite the minimal permutations involved for the hosts, Espanyol will still draw incentive from the fact that taking points off their Catalan neighbours would dent their title bid somewhat.
Recent form: DDDWWD
It would be a miracle should Barcelona finish this season without at least one trophy under their belt. Their treble bid still burns brightly, but victory away to Espanyol would see them consolidate their grip on part one of that prospective achievement.
With second-placed Real not playing until Sunday, Luis Enrique's side can move five points clear at the summit of La Liga with five games remaining.
It is developing into a fine season for the Catalans, who beat Paris Saint-Germain 2-0 on Tuesday to cap a 5-1 aggregate win in the quarter-final of the Champions League, while they also look forward to a Copa del Rey final with Atletico Madrid on May 30.
Should they go all the way on three fronts, it would represent their first treble since Pep Guardiola's Barcelona swept all before them in the 2008-09 campaign - and few would back against Luis Enrique emulating his former teammate at Camp Nou.
They have not tasted defeat in any competition since Juanmi gave Malaga a shock 1-0 win in Catalunya back in February. Since then, Enrique's charges have won 12 of their subsequent 13 games, with a 2-2 draw away to Sevilla two weeks ago being the only blemish.
With their star-studded attacking triumvirate of Luis Suarez, Neymar and Lionel Messi - who have 95 goals between them this season - at their talismanic best in recent weeks, it appears as if nothing can stop Barcelona at the moment - though Espanyol will certainly try.
Recent form: WWWWDW
Recent form (all competitions): Delete this line if irrelevant WWDWWW
It remains to be seen if Xavi Hernandez is fit to take part in Saturday's visit to the Estadi Cornella-El Prat.
The veteran midfielder, who is expected to leave the club this summer, did not train on Wednesday following the win over PSG, putting his participation in doubt.
Meanwhile, Thomas Vermaelen could make a matchday squad for the first time in his injury-hit maiden season at Barcelona.
Espanyol possible starting lineup:
Casilla, Arbilla, Alvaro, Moreno, Duarte, Lucas, Sanchez, Rios, Alvarez, Sergio Garcia, Caicedo.
Barcelona possible starting lineup:
Bravo, Alves, Pique, Mascherano, Alba, Rakitic, Busquets, Iniesta, Messi, Suarez, Neymar.
Head To Head
Messi grabbed a hat-trick as Barcelona won the reverse fixture 5-1 back in December - a win that extended their unbeaten streak over their neighbours to 12 games, with Espanyol winning just four of the last 46 meetings between the sides.
We say: Espanyol 1-3 Barcelona
If there is such a thing as a psychological edge in football, then Barcelona, who have lost just four of their last 46 against Espanyol, must have one over their city rivals.
Despite that ominous stat, we reckon that Espanyol will give a good account of themselves on Saturday, before ultimately being powerless to combat the trident of Suarez, Neymar and Messi.