Reigning champion Nigeria is on the verge of completing a late charge for 2015 Africa Cup of Nations qualification.
The West African side failed to win a single one of its opening three Group A matches, casting doubt over whether it would get the chance to defend the title it won in South Africa in 2013.
Nigeria now sits second after victories over Sudan and Congo, but knows anything less than a win against the already-qualified South Africa could end its hopes of making the tournament in Equatorial Guinea.
Congo - third by virtue of its inferior head-to-head record against Nigeria - heads to Sudan knowing it must better Nigeria's result.
Group E remains wide open, with all four teams still harbouring dreams of qualification.
Ghana leads the way with eight points and a draw against Togo - bottom on six - would be enough to see it through, although it comes into the fixture on the back of a 1-0 defeat in Uganda, and defeat would ensure it finishes outside the top two.
It is impossible for Guinea and Uganda to qualify together automatically, so their encounter is effectively a play-off.
Those who miss out in Groups A and E could be afforded a reprieve, as the pools lead the way in the chase for the best third-placed nation.
Algeria has run away with Group B and heads to a Mali side desperate to edge Malawi to qualification.
Second-placed Mali holds a four-goal advantage over its rival, which visits Ethiopia, so a win should be enough to see it progress.
Group D leader Cameroon has already booked its place at next year's tournament and hosts Cote d'Ivoire in Abidjan this week.
Cote d'Ivoire sits three points clear of third-placed Congo DR, but a defeat coupled with a win for its nearest rival over Sierra Leone would see it miss out on a top-two finish, owing to it having scored fewer goals in matches between the two nations.
Cape Verde Islands and Zambia meet in Group F having already made certain of their finals place, while Mozambique aims to enhance its slim chances of finishing as the best third-placed team at Niger.
It is a similar story in groups C and G, with Burkina Faso, Gabon, Tunisia and Senegal having already qualified, and Angola and Egypt scrapping in third.
Angola heads to Burkina Faso in Group C, while Lesotho is at Gabon, and Group G sees Tunisia host Egypt and Senegal face Botswana.