Losing to New Zealand on Sunday could be very bad news for South Africa. There is a real danger that South Africa will fail to make it to the Super Six.
What must South Africa do from now on?
First, South Africa must hope and pray that West Indies defeat Sri Lanka on February 28.
If Sri Lanka defeat West Indies, then South Africa are eliminated -- even if South Africa defeat Sri Lanka later on March 3!
This is because Sri Lanka are then assured of at least 20 points (with wins or likely wins against Canada (C), Bangladesh (B), Kenya (K), New Zealand and West Indies) and the best that South Africa, New Zealand and West Indies can get are 16 points each (we assume that both West Indies and South Africa defeat B, C and K and have, or will have, at least one win against a 'big' opponent -- respectively, West Indies over South Africa and South Africa over Sri Lanka; we assume that New Zealand will defeat B and C, forfeit K to add to their wins over South Africa and West Indies). Then as per the World Cup rules (Rule 21.9.1), New Zealand will be the first to qualify (having defeated both South Africa and West Indies), followed by West Indies (have defeated South Africa). South Africa (having lost to both West Indies and New Zealand) will be eliminated!
If West Indies defeat Sri Lanka, then they are assured of 20 points (with wins or expected wins over B, C and K and 'big' wins over South Africa and Sri Lanka) and then South Africa (if they beat Sri Lanka), New Zealand and Sri Lanka (if they lose to South Africa) will tie at 16 points. This will lead to a deadlock since Sri Lanka beat New Zealand, who beat South Africa who beat Sri Lanka and the net run rate (NRR) will enter the equation, with the team having the lowest run rate being eliminated. Currently, South Africa are second in the NRR table, behind Sri Lanka -- but ahead of New Zealand and West Indies-- so the NRR factor can't be a great worry.
So things appear grim for South Africa. They must hope that West Indies defeat Sri Lanka, they must defeat Sri Lanka and they must ensure that their NRR is the best, or the second best, in the Group.
Rain might be a bigger saviour for South Africa, especially if either of Sri Lanka, West Indies or New Zealand have to share points with B, C or K.
Any team that drops below the threshold of 16 points could be in trouble.
Finally, let's see what each of the other teams would like the most.
Sri Lanka: Defeat West Indies. This win is crucially important for Sri Lanka because then Sri Lanka will almost surely go through to the Super Six together with New Zealand and West Indies. Having defeated both New Zealand and West Indies in their Group matches, this win assures Sri Lanka an 8-point advantage in the Super Six table! This, they know, is a passport to a semi-final berth.
West Indies: Defeat Sri Lanka so that they sail into the Super Six and then hope that South Africa defeat Sri Lanka so that there is a small chance that South Africa and Sri Lanka, instead of Sri Lanka and New Zealand, join them in the Super Six. This scenario gives West Indies (who have lost to New Zealand) an outside chance of advancing to the Super Six with an 8-point advantage. In any case a win over Sri Lanka assures West Indies of at least a 4-point advantage in the Super Six. If West Indies lose to Sri Lanka and Sri Lanka beat South Africa, West Indies are only assured a lame duck' Super Six position with no points to carry.
New Zealand: Go to Kenya, win and confirm a Super Six berth. Since that may not be possible, hope that Sri Lanka beat South Africa so that they are assured a Super Six berth with West Indies and Sri Lanka and carry forward at least 4 points. New Zealand's best case scenario could have been if both South Africa and West Indies beat Sri Lanka. They could then hope to go up with South Africa and West Indies and carry eight full points! But this entails a small risk: being tied with South Africa and Sri Lanka at 16 points, New Zealand could be eliminated if they have the poorest net run rate (remember that Sri Lanka and South Africa have matches with three weak teams -- B, C and K to improve their NRR while New Zealand might only play B and C).
These scenarios confirm that neither West Indies nor Sri Lanka stand to gain by 'cooperating' to ensure a South Africa elimination. This must mildly re-assure South Africa as they struggle to survive what can only be described as a confluence of evil forces working against them.
First, they were docked one over against West Indies and lose by three runs (and soon this docking business will go!). Then South Africa suffered a little due to the Duckworth-Lewis (D/L) weakness of favouring the team that doesn't lose wickets while chasing a big target. Finally, South Africa's NRR was actually lowered marginally to cover another D/L-related technical anomaly; although South Africa scored at 6.12 per over in their game against New Zealand they were "accredited" only with a rate of 5.8 -- "1 run less than New Zealand's final target score (226-1=225) off the total number of overs allocated to New Zealand (39)" as per the WC rule book.