Barca have won their last six games against their city rivals - conceding just once in the process - and have not suffered a derby defeat in the last 11 meetings between the two sides.
Sergio Garcia gave Sergio Gonzalez's side a shock lead at Camp Nou back in November with Espanyol's first goal against La Liga's leaders for almost three years, but Barca responded in ruthless fashion.
Lionel Messi equalised on the stroke of half-time and went on to score a hat-trick as Luis Enrique's men coasted to a 5-1 victory to heap more misery on their neighbours.
Barca head into Saturday's encounter on the back of beating Paris Saint-Germain 2-0 on Tuesday - and 5-1 on aggregate - to reach the semi-finals of the UEFA Champions League for the seventh time in eight years and they hold a two-point lead over Real Madrid at the top of La Liga.
Casilla can expect to be kept busy if Messi, Luis Suarez and Neymar feature, as the trio have 95 goals between them in all competitions.
The Espanyol keeper is relishing the challenge of facing a star-studded Barca outfit, though, as his side attempt to extend their six-match unbeaten run.
He said: "it is a derby match different from any other.
"To confront Messi, Suarez, [Andres] Iniesta, Xavi, Neymar motivates you more. I'm not afraid of any, but respect them all."
Real also reached the Champions League semi-finals this week courtesy of Javier Hernandez's late goal against city rivals Atletico Madrid on Wednesday.
Carlo Ancelotti is once again set to be without Luka Modric, Karim Benzema and Gareth Bale at Celta Vigo on Sunday, but Marcelo is available to return from suspension.
Third-placed Atleti will be expected to respond to their European exit by beating Elche at home on Saturday.
Diego Simeone expressed his pride following the Spanish champions' defeat at Santiago Bernabeu and has urged them to go on and secure third place.
Valencia will attempt to respond to their 2-0 defeat to Barca by increasing second-bottom Grenada's plight, while bottom side Cordoba are running out of time as they go in search of their first win in 14 matches at home to Athletic Bilbao on Friday.
There is plenty riding on Saturday's clash between fellow strugglers Almeria and Eibar, while Deportivo La Coruna will be striving to climb out of the relegation zone when they make the trip to Malaga on Sunday.
Getafe entertain lowly Levante on Saturday, while Real Sociedad host Villarreal and Sevilla take on Rayo Vallecano in the other game to be played on Sunday.
