Napoli defender Salvatore Aronica was fortunate to stay on the pitch for a tackle on Ngog but Liverpool will feel justice was done when the Italian was punished for bringing down Reds right-back Johnson.
Hodgson's side were showing signs they may steal a win and when Ngog controlled, swivelled and shot, but Napoli defender Aronica had to launch himself to block the strike as the honours finished even and Liverpool stayed top of the group.