Napoli's top four hopes are all but over after the loss.
"We are struggling and physically alone only lasted for the first half," confessed the Coach.
"We paid the price for a strong performance against Lazio on Saturday and today were simply exhausted. We deserved to lose, because we are truly tired and on top have many injuries and suspensions to deal with.
"Every time we are second to the ball and Atalanta were very reactive today. We are not up to the level of the big clubs in terms of experience and strength in depth. To win we have to be at 100 per cent and run harder than the others."