Group D's climax proved to be as enthralling as billed, with Republic of Ireland leapfrogging their way to a play-off spot, while Serbia finished top of the pile.
With Group D finely poised before the evening's fixtures kicked off, it was Dušan Tadić's Serbia who emerged triumphant.
The midfielder played 90 minutes in Serbia's 1-0 victory over Georgia, ensuring they topped the group and won an automatic spot on the bill of Russia 2018.
Elsewhere, Cardiff City Stadium played host to a nail-biter between home nations Wales and Republic of Ireland, with the latter prevailing in a tightly contested affair.
Saints striker Shane Long was forced to watch on - missing out with a hip injury sustained against Moldova - but a James McClean goal in the 57th minute ensured Martin O'Neill's side overtook their Welsh counterparts in Group D standings.
Italy also concluded their qualifying campaign with a 1-0 away victory over Albania, where Saints' Manolo Gabbiadini was a late second-half substitute.
Azzurri had already secured a play-off berth prior to tonight's proceedings, and they will join Ireland in next Tuesday's play-off draw in Zurich.