"In recent years I have never seen such a bad approach to a game as today. We will talk this over during the week and analyse it carefully," said Gasperini.
"We must immediately get back on track and avoid ruining everything we've worked for up until now with a bad end to the season."
Diego Milito made his comeback a month after a thigh strain, but even their top scorer could not find a way through.
"It's not that they are sluggish or workmanlike, but you need to be efficient and have the right concentration in the closing weeks of the campaign, a time when everyone gives their all.
"Genoa can end the season on a high and between us we must find a way to turn this around.
"A defeat can happen, but not with an approach like the one we took today."