Lazio captain Stefano Mauri says they cannot dwell on derby defeat to AS Roma.
Mauri admits their Champions League hopes are in now in the balance.
"We deserved something more against Juventus in the Coppa Italia and the same is true here," he told Sky Sport Italia.
"I got a knock from Daniele De Rossi, but it was accidental. These things happen, it's not an issue.
"The game went badly today and it will not be easy, but we have one more round left and have performed at a very high level throughout the campaign.
"We deserve to be in the Champions League and must get the result against Napoli at all costs."