The Argentinian was appointed after Betis sacked Juan Carlos Garrido this week and he will make his debut in Friday's match at Celta Vigo.
Garrido, who had only replaced Pepe Mel on December 2, had failed to steer Betis to a single league victory and was shown the door after Saturday's 5-0 home loss to Real Madrid.
"Garrido was a serious manager but he had no luck," Amaya said. "Now we are all behind Calderon, who is more cheerful.
"We have full confidence in Calederon, he is a coach that transmits happiness."
Betis have won just two Primera Liga games this season, their last a 1-0 triumph over Villarreal on September 29.
Ten defeats and three draws have followed since.
"We, the players, feel terrible," Amaya said. "However, if on Friday we can take a win in Vigo, we will truly start believing that we can avoid the drop."
Last weekend's reverse against Madrid left Betis at the foot of the standings with 11 points, eight adrift of safety.
"We hope that this coaching change will spark the team and that on Friday we can take three points in Balaidos," Amaya said.
"I believe that this coaching change will be a positive one."
Celta striker Mario Bermejo is not taking Betis lightly despite their rival's dismal run of form.
"They have a very good roster," he said. "If you look at player by player, they have a very good side.
"We cannot forget that last season they qualified for the Europa League and this year they are still alive in the European competition.
"Betis have to win at all costs if they are to have any chance of avoiding the drop and we cannot think that just because they are the bottom-side we will score three goals against them."
Celta, who beat Betis 2-1 in Seville earlier this season, go into the encounter on the back of Saturday's 1-0 loss at Espanyol, their second defeat in three games.
The outcome dropped Celta to 16th in the standings, three points clear of the drop zone.
Celta coach Luis Enrique will be bolstered by the return of the team's top scorer Charles, who missed last weekend's game with a stomach flu.
However, the home side will have to overcome the absence of midfielder Augusto Fernandez, who must serve a one-match ban.