Victory over City would send Liverpool 11 points clear at the top of the table.
And Robertson warned they must be on their game this afternoon: "Certainly since I've been here, our record there isn't great from my memories, maybe we've had a couple of draws and things like that. It's always been a tough place for us.
"They've got some fantastic players. OK, they're maybe having a tough season but I think they showed last weekend against Newcastle they can still steamroll teams and things like that.
"We have to be at our best, that's the only way to do it. And if we are at our best then we believe we can cause any team problems.
"But it's going to be difficult. We need to recover, rest as much as we can because the schedule has been tough – but we'll be ready to go on Sunday."
He also told liverpoolfc.com: "The whole squad has to be ready, the manager keeps on saying that, the lads on the bench have to be ready to make an impact.
"Once we get through the next two games then we've got a little break where we've not got a game at the weekend.
"We just need to keep pushing through that and if we do then let's see where we're at after that."