The 2010 winners beat Valencia 2-1 on Wednesday night but still went out on away goals and following three consecutive league defeats doubts have been cast as to whether he will make it to the end of his first season at the club.
He told Spanish sports daily newspaper Marca: "I see myself as absolutely capable, as is the squad, to turn this situation around. If we maintain our level then very soon our results will change.
"Watching the team I refuse to believe that we will not be challenging for a Champions League place and with the incorporation of (Jose Antonio) Reyes into the squad we will have even more options in attack. We have demonstrated what we can do and we can play. Hopefully this is the turning point."
Fernando Navarro is suspended for the hosts but Manu Del Moral returns from his one-game ban and Jesus Navas should shake off a knock to retain his place on the right.
In contrast Espanyol come into the game on a high after Alvaro Vasquez's late goals against Barcelona and Cordoba in the past week ensured a point in the Catalan derby and progression to the last eight of the cup.
Manager Mauricio Pochettino though wants his side to be fully concentrated on trying to move ahead of their opponents in the league table this weekend.
He told a press conference broadcast on the club's website: "We cannot think about Tuesday because if we are distracted and don't think about the Sevilla game it will cost us.
"Sevilla will be hurting because they have gone out of the cup despite, from what I saw, being the better side against Valencia. We are conscious of the fact that we will have to work very hard and play to a very high level to take the three points."
However, despite his side's good form Pochettino does have some selection problems ahead of the trip to the Sanchez Pizjuan.
Sergio Garcia is suspended, whilst Christian Alvarez's injury means that youngster Kiko Casilla will continue to deputise in goal. Ndri Romaric is also unavailable as part of his loan deal from Sevilla but Walter Pandiani and Juan Albin do return to the squad after long-term injuries.