The Barcelona-based club were rooted to the foot of the table when Aguirre replaced Mauricio Pochettino at the end of November with just two wins from their opening 13 games.
However, since the Mexican took charge Espanyol have picked up six wins and four draws from 12 league matches to climb up to 13th in the table, with their only defeats coming away to top two Barcelona and Atletico Madrid, who they lost 1-0 at last weekend.
Espanyol's tally of 31 points leaves them almost as close to the European places as they are to the drop zone, but Lopez is only thinking about safety heading into tomorrow's visit of Real Valladolid.
"Europe? We have to stay focused. We had a very tough and difficult start to season and right now we cannot think about that. We cannot forget that we've come from a critical situation. We have to think about getting to 42 points," he said.
"We need to assure our place in the division. Anything else would be a gift."
Espanyol's impressive revival has been built around their superb home forward, which has seen them pick up 16 points from a possible 18 at Cornella-El Prat under Aguirre.
Lopez hopes they can continue that run against a Valladolid side who earned an impressive 2-1 win at Europe-chasing Rayo Vallecano last time out.
He said: "Valladolid are coming off an away win which will give then a lot of encouragement, they are playing pretty well and they will be a complicated opponent who are going to make things difficult for us. We have to make the most of playing at home and the fact we've won several consecutive games.
"Cornella is key, we can do good things here."
Valladolid's win over Rayo was their first victory in five matches and lifted them up to 11th on 33 points, two more than Espanyol.
Coach Miroslav Djukic is also looking to aid his side's bid for safety with a victory tomorrow, saying: "We go out in every match with the intention of winning and we want to seal our Primera Division status as soon as possible."