Real coach Manuel Pellegrini opted to rest Raul and the Portuguese wizard following their midweek international excursions at the newly-built, if unfortunately named, Estadi Cornella-El Prat as his side set out to make it two wins from two.
Espanyol created the better of the chances for the majority of the first half with Real being reduced to a couple of speculative long-range efforts on an atrocious surface.
The recently laid turf was cutting up throughout the game and seemed to affect the mentality of the players.
Former Celtic star, Shunsuke Nakamura, whipped in an in-swinging free-kick that was headed back into the melee in the six-yard box and Hurtado Moises flicked the ball towards goal, only to be denied by Casillas low down at his near post.
Heartfelt banners were on display around the ground in remembrance of tragic late captain Daniel Jarque, who suffered a fatal cardiac arrest in August.
The home side again came close on 35 minutes following a clever chipped pass over a sprawling Casillas and into the path of Raul Tamudo just yards out before Alvaro Arbeloa came across to make a vital interception with the goal gaping.
Three minutes later, Real fired a warning shot.
GutiÃ¢â‚¬â„¢s ball into the box was expertly chested back by Kaka towards his arriving compatriot Marcelo, whose drilled effort was saved by Kameni in the Espanyol goal.
Their next attack was not a warning.
Debutant Esteban Granero played a delightful one-two with Kaka into the box and finished emphatically on the 22-year-oldÃ¢â‚¬â„¢s Los Blancos return following a loan-spell with Getafe.
Espanyol playmaker and former Barcelona star, Ivan De La Pena, made his entrance after the break and installed greater creativity into the home sideÃ¢â‚¬â„¢s midfield.
The travelling fans had to wait until after the hour mark before the introduction of the worldÃ¢â‚¬â„¢s most expensive player as Ronaldo replaced fellow summer arrival Karim Benzema.
Real doubled their advantage through Guti on 77 minutes.
The instrumental Kaka gracefully drifted past Chica in the penalty area and cut the ball back to the Spaniard who wrong-footed the goalkeeper with a low drive into the bottom corner.
Ronaldo then fell victim to the terrible pitch conditions after dribbling past two and cutting inside from the left only for a bobble to send his shot high and wide.
But the winger Ã¢â‚¬â€œ full of tricks and step-overs Ã¢â‚¬â€œ had the last laugh as he wrapped up the scoring in stoppage time.
Guti played him in with a superb ball from the outside of his left boot and Ronaldo drove into the box and placed the ball neatly between the legs of the despairing Kameni to bag MadridÃ¢â‚¬â„¢s third and his second in as many games.
Espanyol: Kameni, Chica, Forlin, Pareja, David Garcia, Moises, Verdu, Luis Garcia, Nakamura (De La Pena, 45), Alonso (Coro, 45), Tamudo (Callejon, 85)
Real Madrid: Casillas, Arbeloa, Albiol, Metzelder, Marcelo, Alonso, Granero, Guti, Kaka (Lass, 81), Benzema (Ronaldo, 66), Higuain (Raul, 75)
Man of the Match: Kaka Ã¢â‚¬â€œ ignored the numerous cynical fouls to create the opening two goals and inspire his new club to victory.
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