South Africa is currently fourth but can leapfrog India, England and Australia if they win all five matches of the series.
If the Proteas achieve this series result, then the side will win the ODI Shield as well as USD 175,000 as the top three sides have no ODIs scheduled before the April 1 cut-off date and South Africas position will be assured.
South Africa have previously won the ODI Shield twice, firstly when it finished as the number-one ranked ODI side in 2008 and then again in 2009.
If South Africa wins the series 4-1, then they will move ahead of England into second position and will collect a cheque of USD 75,000 to compliment the prestigious mace and USD 450,000 which they have already won by sealing the number-one position on the Test Championship table.
In contrast, sixth-ranked Pakistan can move to as high as fourth. But for this to happen, they will have to win all five ODIs of the series.
If Pakistan blank out South Africa, then they will jump from 107 ratings points to 114 ratings points, while South Africa will drop 10 ratings points and plummet to 102 ratings points.
If Pakistan beat South Africa 3-2, then both sides will be locked at 109 ratings points, but South Africa will be ranked above when the ratings are calculated beyond the decimal point.
This ODI series is a precursor to the clash between the two sides in the ICC Champions Trophy, which will be staged from June 6 to 23 in England and Wales.
South Africa won the inaugural edition in 1998, and is drawn in Group B of the tournament, alongside 2004 champions West Indies, 2002 co-winners India and Pakistan.
South Africa and Pakistan will meet on June 10 in a day-night match at Edgbaston in Birmingham during the group stage of the ICC Champions Trophy 2013.
Group A of the ICC Champions Trophy 2013 includes defending champions Australia, 2000 champions New Zealand and 2002 co-winners Sri Lanka, along with hosts England, who reached the final when they last staged the event in 2004.
The tournament opener at the ICC Champions Trophy will feature two former winners, when South Africa takes on India at Cardiff on June 6. The following day, West Indies will face Pakistan at The Oval.
The semi-finals of the ICC Champions Trophy 2013 will be staged at The Oval (June 19) and in Cardiff (June 20), while Edgbaston will be the venue of the final, to be played on June 23.