Who is set to reach the World Cup play-offs in Europe? How does the format work? And could Northern Ireland and the Republic be drawn together? We take a look here.
Scotland missed out after slipping to third behind Slovakia in Group F but Northern Ireland's spot in the play-offs is guaranteed and the Republic of Ireland squeezed in at the expense of Wales, thanks to a 1-0 win on Monday.
The eight play-off sides were confirmed on Tuesday evening, but who could Republic or Northern Ireland face? Here we explain the format...
How do the play-offs work?
Only eight of the nine teams who finish second were eligible for a play-off spot, meaning one team with the least amount of points missed out - that was Slovakia.
Eight runners-up will then be drawn into four pairings, with two-legged play-off ties set for November 9-11 and 12-14, 2017.
The away goals rule will be used to determine a winner of the ties if scores are level after the second leg - whether after 90 minutes or extra time - and four play-off winners will advance to Russia 2018.
FIFA has confirmed that teams will be seeded for the draw on October 17, with the top four teams according to the FIFA rankings in one pot and the remaining four in another.
Who will be seeded?
Northern Ireland and the Republic of Ireland will be unseeded for next week's World Cup play-off draw, when they will learn if they will face either Switzerland, Italy, Croatia or Denmark. This means they cannot face each other in the November play-offs.
Their task has been made harder by the fact the draw for those play-offs, which will take place in Zurich on October 17, will be seeded based on the world rankings published a day earlier.
It is already possible to project those rankings, though, and Switzerland, Italy, Croatia and Denmark will be the four highest, meaning they will be seeded, while Northern Ireland, Sweden, the Republic of Ireland and Greece will not.
The seeded team will not necessarily have their home leg first, as there is a separate draw to determine which countries are at home first.