"I think the Kop will be the difference. At Stamford Bridge it was very quiet but it's not going to be quiet tonight that's for sure," he said.
But the ex-Liverpool keeper admitted the Reds would have to be on top form to get the right result.
"They are going to have to go all out attack. They have got nothing to lose, but they have got to be very tight at the back, not allow Lampard, Cole or Drogba to get into good positions. They have got to pick up the second ball from Drogba and make sure they shut down the midfield," Grob said.