Who could miss out on the World Cup play-offs? What Wales, Scotland, Northern Ireland and Republic of Ireland must do to avoid being unlucky runners up
There are just two rounds of group stage matches to go in the UEFA World Cup qualifying campaign, and a number of nations stand on the cusp of next year’s tournament.
Belgium are the only European side to have qualified from the group stage to date, and they will be joined by the other group winners in Russia.
Four other nations will also qualify for the finals tournament via the play-off route.
UEFA’s qualifying system for the 2018 World Cup saw nine groups of six teams drawn, with each nation playing every other nation in their group on a home-and-away basis.
In all, every country will play 10 matches (eight have been played so far with the remaining two scheduled for October), but, for the purposes of deciding which teams qualify for the play-offs, the results against the sixth-placed team in every group will be discarded come the end of qualifying.
So, only eight matches count when the second-placed teams are ranked to discover who will feature in the play-offs.
The play-off system
There are four UEFA play-offs scheduled to decide the final European teams to make it to the World Cup - but nine groups.
So, to whittle the teams down to eight, the lowest ranked second-placed side are knocked out - with the remaining nations drawn against one another in the two-legged play-off matches, on a seeded basis.
Who has already qualified (at least) for the play-offs?
At the end of the September international break, four teams had guaranteed at least a place in the play-offs.
Switzerland (24 points) and Portugal (21 points) are guaranteed the top two places in Group B, with them still vying - and yet to play each other - in the hunt to win the group.
Whichever side finishes second already has enough points to know they will feature in the play-offs.
Germany (Group C) and Spain (Group G) are in a similar situation, with their points tallies of 24 and 22 respectively meaning they are certain to reach the play-offs if they fail to win their groups.
Who will definitely finish in the top two, but are not yet guaranteed a play-off spot?
Northern Ireland are guaranteed to finish in the top two in Group C, and - as unlikely as it may be - they can still topple Germany to win it, while Serbia have booked themselves a top two finish in Group D and will be looking to win the group ahead of Wales and the Republic of Ireland. But as it stands neither of these nations are certain to be in the best eight runners up, should they finish second in their group.
Who can miss out on the play-offs?
England can still miss out on a top two finish in Group F, though it would take a collapse of historic proportions. The Three Lions are six points clear of third-placed Slovenia, so need just one point to secure a top two finish, while a win in their next game - against Slovenia - will guarantee top spot.
Despite Northern Ireland securing a top two finish, they are not guaranteed to make the play-offs. However, their current points tally of 13 (with points won against San Marino removed) currently places them second in the play-off table, behind Portugal.
Michael O’Neill’s men are ahead of Italy on goal difference, and know that two more points guarantees a top eight finish. One more point will mean Norn Iron rely on their goal difference to remain off the bottom, while they will need other sides to drop points if O’Neill’s side remain on 13 points after their next two matches.
Scotland are in a more precarious position, as they currently sit fourth in Group F. They are just one point behind second-placed Slovakia, and welcome them to Hampden Park for their next match. They then play Slovenia away, and must win both matches to secure second place.
That would leave the Scots on 14 points, after removing the points won against sixth-placed Malta, and would put them in contention of making the play-offs - with it likely coming down to goal difference if no other sides drop points.
Group D, which includes both Wales and the Republic of Ireland, is sure to provide some seriously interesting matches in the next international break.
Serbia lead the group with 18 points, four more than second-placed Wales; Ireland sit one point behind Chris Coleman’s side.
And the final game of the group pits them against one another in Cardiff.
Both Wales and Ireland are expected to win their next match - against Georgia and Moldova respectively - which means that second spot will rest entirely upon the clash between the two nations.
A Wales win would send them to 14 points (with points against Moldova removed), which, as outlined with Scotland, should be enough to guarantee a play-off place depending on goal difference.
An Ireland win would put them on 13 points (with points against Moldova removed), a rather low tally. Martin O’Neill will be relying on other sides to drop points to ensure they are not the worst ranked second-placed team.