FIFA have confirmed the seedings for the World Cup qualification play-offs will be based on world rankings.
The Republic of Ireland are hoping to be among the eight best group runners up when the play-off draw is made on October 17.
Last night's 1-0 defeat to Serbia at the Aviva Stadium means the Boys in Green have dropped to third place in Group D.
The Irish hopes of qualification will all hinge on the final two games of the group in October.
Ireland will play Moldova on October 6 and finish the group away from home against Wales on October 9.
O'Neill's side must secure six points and hope other results go their way to be among the eight teams who enter the play-off.
Ireland are currently 29th in the World Rankings so would be unseeded for the play-offs.
It means they could be drawn against the likes of Portugal, Italy, Sweden or Iceland - should they qualify.