That deficit will seem small fry to the home side, however, who came from 2-0 down at the halfway stage of their quarter-final tie against Anderlecht before advancing on penalties.
The Dutch side also have an outstanding record at the AFAS Stadion to protect, having gone 25 home matches unbeaten in European competition.
“There is very little in it,” Moyes said. “If it was the other way around, if we were a goal down, we would be saying we still have to go for it and that we have a great chance.
“I don’t see it being a big advantage. It is an open game and we are going to have to take it on.
“It’s a huge game. We want to reach a cup final. It would be great for the football club if we could do so. We have really difficult opponent. We’re going to have to earn it. There’s no gimmies in football.”
The Hammers are all-but certain of Premier League survival following Leicester’s defeat to Liverpool on Monday night, and Moyes’s decision to make nine changes to his side for Sunday’s loss at Brentford told of his shift in priorities towards Europe in the final weeks of the campaign.
Lifting the club’s first major trophy since the 1980 FA Cup success stands as motivation enough, but with the winners qualifying for next season’s Europa League, there is also the possibility of securing a third successive campaign in Europe, despite their lowly league position.
“It would be huge if we can make Europe again,” Moyes said. “I have said many times, when you are trying to build and grow a football club it does not always go in the one direction. Sometimes you have setbacks, sometimes it does not go the way you want it to go.
“But I think being in Europe, mainly for our supporters, for the club and for everybody involved it has been an incredible journey. To be in the semi-final last year was a great run for us and this year we have got ourselves in another semi-final. It takes some doing.”