Benitez felt they were denied a clear penalty when Steven Gerrard’s free kick hit Cesc Fabregas’ hand in stoppage time.
Benitez told Sky Sports: “I think so. I think that it was very clear.
“The referee said to our players to be careful and not put your hands too high. It was unbelievable to see the replay and how he could not see it.
“I think we have to analyse the game on not just one decision. Clearly it was a mistake, but the game was difficult against a good team.”
Benitez added: “I think in the second half we were pushing and could have got at least a point.”