The defending champions at Under-21 level lost 2-1 in the second leg last night, with that result meaning that they will not take part in the competition next summer.
"We gave everything but in football the best team does not always win. They had two shots on goal and scored twice," Celades told reporters.
"I thought we played well and had a lot of the ball, but it did us no good. It's very hard to take because we did not deserve this outcome.
"We tried to resolve things right up until the last second but could not turn things around, so we are left with a bad feeling and the dressing room is really down because these guys have given everything."
The Under-21 European Championships will take place in the Czech Republic.