The 1-0 win over Javier Aguirre's men was Granada's first win in 10 games and lifted them out of the relegation zone.
Alcaraz said the win had lifted his side, but he knows Saturday's game against Malaga will be tougher.
He told a press conference: "Wining always reinforces what you have been working on, but each game is different.
"We know that the game [against Malaga] could be more uncomfortable for the players [than the game against Espanyol] because each game requires different things of you."
He also called on his players to repeat the commitment they showed against Espanyol and in their last home match, a 1-1 draw with Valladolid, in which they were unlucky to not take all three points.
"We'll try and have a very clear plan and I hope we are capable of developing it like we have done in the last two games," he said.
"We have to renew our efforts, try and make as few errors as possible and play with character, strength and determination."
Alcaraz expects Granada to take the initiative in the match, because they will be playing in front of their own fans.
"At home we should be determined to go for the match, play in the opposition's half but without losing space or rhythm," he said.
"Malaga are a top team that got to the latter stages of the Champions League. We have to know them well if we are to cause them damage. My job is to try and come up with a plan so that we play better than them."
Malaga goalkeeper Willy Caballero knows his side will be in for a tough time when they travel to Granada, because he has personal experience of what it is like to fight a relegation battle.
He told reporters: "We were in their situation a few years ago and those teams that are fighting at the bottom are playing for their lives, so we have to do the same.
"Even though we are in a better position than them in the table, we will have to match their intensity."
The Argentine goalkeeper also stressed that a victory on Saturday was vital if his side is to have any hope of clawing back the five-point gap between themselves and Real Sociedad in the fight for that final Champions League spot.
He said: "The three points available this week are very important if we want to stay at the top. Even though finishing in fourth place is not in our own hands, it's still vital we win. If we don't, it'll be even harder."
Granada midfielder Recio, on loan from Malaga, will be unable to play the game due to the terms of his contract.
Manuel Pellegrini's side, meanwhile, will be without the injured Jeremy Toulalan, substitute goalkeeper Carlos Kameni, who has had to return to Cameroon for personal reasons, and Eliseu, who has been rested and will not travel to Granada.