At the moment, Gerrard is providing nowhere near enough on the ball to make up for his defensive shortcomings. You could see on the third goal, where he runs into the middle instead of tracking his man that he's just not learning how to do it properly.
We got away with it when we were buzzing around teams all game long and didn't give the opposition multiple chances every game to exploit our frailty, but we're getting twatted now.
Gerrard was clearly told not to defend at that point as he was too tired, hence we saw him up around their box and sticking around it. I don't think anyone was to defend there, Brendan went all in and Sakho fucked up a header and Skrtel gave too much space and Mignolet was a statue
That said, he was fucked and should be dropped for a game at least