Northern Ireland will leapfrog Romania to the top of Group F with 15 points from six matches if they can beat the visitors at Windsor Park on Saturday.
“I’ve said all along that 18 points is going to all-but guarantee you finish in the top three finish, but in our group it may actually guarantee automatic (qualification),” O’Neill told Sky Sports News HQ.
“So if we can get 15 points after this game with four games to get the remaining three points, that’s a strong position to be in.
“Our aim is to keep this distance between ourselves Hungary and Finland and also to increase that if possible and three points will help us do given that they are playing each other.”
Northern Ireland have never played in a European Championships but O’Neill is refusing to get ahead of himself.
“We’re not looking at it as five cup finals or over-emphasising the significance of this game,” he said.
“The important thing for us is we will be competitive right until the end of the group. The four wins we have had to date will ensure that and we aim to hopefully get another two victories as soon as possible.
“Saturday night provides us with the first opportunity to do that.”