It was Gerrard who struck the winner in the 2-1 result and Benitez said: "I would have wanted really to leave Steven out of the match. But we have too many injuries and Momo was sick again, so he had to play.
"And in the end he was the one who scored the vital goal. Cardiff worked very hard and were always dangerous from set-pieces, and that is where their equaliser came from.
"But then Gerrard got through to score a typical goal. His form is coming back, as are his goals. That is three now in successive games."
Jones said: "It was Gerrard that really killed us - only he could have turned the game like that. So I'm going to have to get my son to duff him up in training!"
Liverpool took the lead through French youngster Nabil El Zhar with a stunning 20 yarder in the opening minutes of the second-half.
Darren Purse headed Cardiff level, but Gerrard stormed through to grab the winner while the Welsh hordes were still celebrating.