Peter Crouch says the way the Reds turned that game around gave the team the belief that they could go all the way to Cardiff.
"A couple of fans have said to us that after we'd had a result like that, that you do sense it is meant to be. Obviously at the club there are still the memories of Istanbul and the comeback there," said the England international.
"It happened through that run last year. The other lads were telling me about the moments when they thought they were out, especially the Olympiakos game when they scored three in the second half to go through and Steven Gerrard scored that screamer to win it.
"In the FA Cup this year it's been the same. To be honest, we were going out at Luton. We were 3-1 down and looking beaten but somehow managed to pull it round.
"Since then we beat Manchester United and Chelsea and there's one more step to go. We've gone about it the hard way but we've managed to do it.
"We all know that the job isn't done yet. We've done well to get there but it will count for nothing if we don't beat West Ham - we've got to win this thing now.
"Outsiders looking in might think it's a done deal and we've only got to turn up to win it but I can promise you we're not thinking like that. And with the manager we've got, there is no danger of us having a lapse of concentration."