The Serbian coach has seen his side win only one of their last seven league fixtures and Sunday's 2-1 loss left them 11th in the Spanish top flight.
Valencia had more possession than their hosts but succumbed to debutant Cristian Herrera's late goal.
Djukic insisted his side had played well despite their defeat and rued the fact they could only convert one of their eight shots on target.
"We played our best game of the season because we dominated the play and created some good opportunities," he said.
"However, with each passing minute it weighs on your mind when these are not converted into goals.
"Nonetheless, we must to continue to work hard as playing well has not earned us anything.
"We had a defensive failure for Elche’s second goal when we were going forward to try and win the game, and we paid for it.
"We need to improve our concentration and some defensive aspects."
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