There are nine qualifying groups but only eight play-off places available.
Uefa rules stipulate that results against the bottom-placed side in each group won’t count when determining which eight teams advance to the two-legged knockout round.
Scotland are aiming to avoid being the “worst runners-up” – the team with the lowest total of accrued points when results against the basement side are subtracted.
Wales’ victory over Georgia in Tbilisi last night, coupled with Republic of Ireland’s home win over Moldova and Serbia’s 3-2 loss to Austria means that there is all to play for in Group D, with Serbia, Ireland and Wales all able to finish top or in the play-off spot.
The most likely outcome is that Serbia beat Georgia on Monday to finish top of the group while Wales (17 points) and Ireland (16 points) will battle it out for the play-off spot. Wales just need to avoid defeat to finish second while only a victory will suit the Irish.
Whichever team finishes second in Group D will likely finish level with, or below Scotland on total points after results against bottom-placed sides are removed.
The other group that could have a bearing on Scotland’s final position is Group H, where Bosnia & Herzegovina, Greece and Cyprus are all vying for the runners-up spot.
The worst runner-up will almost certainly be decided on points total but if that still doesn’t separate teams Uefa will use goal difference, then highest number of goals scored, then ‘Fair Play’ points and finally the drawing of lots.
As things stand, the worst runners-up are likely to be Wales or Ireland in Group D or the second-placed side in Group F if Scotland fail to beat Slovenia or the Group H team which finishes second.