Blerim Dzemaili and Lorenzo Insigne were on the scoresheet for Benitez's men at the Citta del Tricolore.
Benitez, whose team are third in the Serie A and four points behind Roma, praised his team for maintaining their standards despite a busy run of games.
"If we see a team playing with this level of intensity despite it being the third game in eight days, then I can only be satisfied," he told Sky Sport Italia.
"Of course we can always improve. Marek Hamsik is sharper now and has more match fitness, so we're starting to see his quality emerge too."
The Argentine may miss Thursday's UEFA Europa League clash against Swansea.
"We can't say anything now, as we have to perform some tests tomorrow. I can't say if he'll play on Thursday, but we have time to evaluate the situation," Benitez said.
"It will be extremely difficult, as Swansea play good football and won't let us keep possession for long."
