Los Che are scheduled to play their first home game since the sacking of Mauricio Pellegrino and have started positively with three consecutive wins under new coach Ernesto Valverde.
And Parejo insists they will be giving it their all against 13th-placed Rayo and feels a new coach has brought a fresh approach to the side.
"I believe the fans are eager to see a change in the level of our commitment," he told reporters.
"We will win the game this weekend, we will go out to get the three points, the fans want to see a team that will give it all and we are willing to do it.
“We are not the first to not like losing. After Malaga and Real we were hurt, but we have taken a step forward.
“We have been helped by the change in coach, but we have also wanted to show that it was a one-off mistake that we would not repeat again.”
When asked if his individual performances and his goal in the game against Osasuna on Tuesday have made him more confident at the club, he responded in a positive manner.
He added: "Scoring goals is great and can give you confidence, but most confidence comes from training.
“Under Valverde, something has changed, but I’m not sure what. The team looks different and we are more intense. As I see it, though, I had as much of a chance under Pellegrino as I do now.”