Tommaso Rocchi insists Lazio have to get over Sunday's 2-0 defeat to Roma in the Derby Capitolino.
Lazio have lost five in a row to their bitter rivals, but still lie ahead of them in Serie A.
The Aquile are fifth in the standings and still have a chance of qualifying for the Champions League.
Speaking to Lazio Style Radio, Rocchi said: "We apologise to all the fans. They have every reason to be angry. I have lived here for seven years and understand their suffering.
"I am one of those people who loves Lazio. The anger is even greater after losing five derbies in a row. The dressing room is also distraught.
"Unfortunately, we'll have to wait until next year to change the verdict in the derby, but now we must all stay united to realise our objectives.
"We have had an exceptional season. We deserve our position in the table. For this reason we can't throw everything to the wind.
"The next games will be decisive for qualifying for Europe. We have the task of believing that we can finish in the top four."