Guardiola's men ease to victory over the Periquitos as they move eight points clear of Real Madrid, and to within on of the title.
Andres Iniesta opened the scoring in the 29th minute when he capitalised on Ernesto Galan’s mistake.
The full-back’s heavy touch allowed Iniesta to steal the ball and charge toward goal where his trickery created space to shoot inside the area. The Spanish midfielder steadied himself before powering a low drive beyond Carlos Idriss Kameni to assert Barcelona’s dominance on the tie.
Espanyol held their own until the break but the found themselves two down soon after the interval with Gerard Pique met Xavi’s corner with aplomb to double Barca’s lead.
Barcelona failed to begin in their usual fashion as Espanyol effectively denied the Blaugrana time and space on the ball in the opening exchanges.
They did, however, find their feet and when Lionel Messi found himself in promising positions he looked to exchange passes with his teammates but the Argentine was left frustrated when the ball was never returned.
Barca were reminded of the threat that Espanyol presented on the counter-attack when Ivan Alonso and Osvaldo combined well before the latter was disposed by a recovery challenge from Javier Mascherano.
With Barcelona aware that goal would be invaluable they were able to test the glove work of the Carlos Idriss Kameni through Pedro and Andres Iniesta.
The Columbian stopper was required to get down low to beat away Pedro’s shot before Iniesta rehearsed his goal. The Spanish international turned his marker around with quick feet before he tried to curl an effort into the far post, only for Kameni to thwart Iniesta with a fine stop.
Espanyol responded when they showed pace on the counter attack giving Jose Callejon a chance to find Ivan Alonso waiting in earnest to turn it home but the cross was behind Alonso allowing Gerard Pique to hack it clear.
Lionel Messi became more determined and when he brought a seemingly impossible ball down out of the air it seemed as if the goal was sure to come. The Argentine burst into the penalty area before crashing a cross-come-shot across the face of the goal.
Barcelona’s pressure eventually reached its toll when Ernesto Galan gifted the ball back to the opposition.
Andres Iniesta proceeded in flirting with the defender before he turned Raul Rodriguez and hammer a low drive beyond Kameni to establish Barcelona’s inevitable lead.
That lead should have been doubled when David Villa burst onto Iniesta’s through ball but the Spanish striker failed to hit the target after Barcelona played the beautiful game at its most beautiful.
Andreu Falon touched the ball too Messi whose quick flick allowed Iniesta to send a first-time pass into Villa but the World Cup winner put his shot wide; cue a disappointed sigh around the Camp Nou.
Kameni was called upon before the half-time whistle when Messi’s surge forward drew in three Espanyol defenders. The Argentine, in the hunt for the Pichichi, unselfishly tapped the ball to Villa but the striker was fractionally beaten it after a brave lunge from the Columbian stopper.
Team United Barcelona line-up ahead of their clash against Espanyol
Barcelona’s second goal came from the most unlikely of sources soon after the break; Gerard Pique. The Spanish defender battled hard to get to Xavi’s corner ahead of his marker and Pique’s downward header doubled the Blaugrana’s lead.
Osvaldo attempted to revive Espanyol’s pursuit of European glory as he left Pique on his backside. The Italian stung the palms of Victor Valdes after passing the Spanish defender, and soon after spun the same man in the area but his bending effort was clung to in the air by Barca’s ‘keeper.
The game became tepid until Messi’s burst of energy won the Argentine a free-kick on the edge of Espanyol’s ‘D’, with the same player looking determined to take advantage of the set-piece.
Messi was forced to focus for two minutes as the Pedro and Raul Rodriquez shared words in the wall, but it was the same wall that denied the Argentine the chance of scoring his 32nd goal of the season.
Barcelona continued to search for the third goal of the tie and when Messi’s reverse pass to Iniesta left the Spaniard the chance to roll it across the six yard box to either Villa or Pedro it should have came but for a superb touch over the bar from Rodriquez.
Neither side showed much urgency in the latter stages of the game as the clock neared the 90 minutes, Eric Abidal was introduced in his continuing recovery from his operation to a cheer around the Camp Nou.
The win takes Barcelona to within point of la Liga Championship with three games left to play, the first of which is against Levante on Wednesday.
Espanyol, meanwhile, will continue their pursuit of European glory as they hope to close in on sixth placed Atletic Bilbao, and that last Europa league spot.