Betis' 2-0 victory over Getafe on Saturday was just their second league win in their last 20 matches, with first-half goals from Leo Baptistao and Ruben Castro cutting their gap to safety to eight points.
The Seville club have been bottom of the table for the vast majority of the season, but Calderon feels their run to the last 16 of the UEFA Europa League - where they will face local rivals Sevilla - has helped.
"The dynamic has changed," he said.
"Since beating Rubin Kazan (in the Europa League last 32) we're improving. We're still lacking a lot but the feelings are good. We have to keep working hard and improving.
"We're taking it a game at a time. Next we play Sevilla (on Thursday) and then we'll start thinking about Sunday's game (against Elche).
"While it's still mathematically possible we can stay up, we'll keep believing."
