Edinson Cavani broke the deadlock from the penalty spot in the 50th minute before netting his second of the evening in the late going and Ranieri conceded that the Azzurri deserved all three points.
"The penalty episode is something I need to review but Napoli were superior," he told reporters after the game. "This defeat does not erase all the good things we have done this season.
"We accept the result on the pitch and must now focus on the match against Shakhtar Donetsk," the 59-year-old tactician added.
Roma will lock horns with Shakhtar in the first leg of their Round of 16 tie in the Champions League on