South Africa had entered the series against Sri Lanka, trailing number-one ranked Australia by four points. However, Australia's 0-2 defeat against New Zealand and South Africa's own 5-0 win over Sri Lanka means the Proteas have now moved ahead of the world champions. In the 5th and final ODI, South Africa defeated Sri Lanka by 88 runs.
A delighted South Africa captain AB de Villiers said: "We are excited to be back at the top of the ICC ODI Team Rankings. We have had some trials since the World Cup two years ago but have worked hard to rebuild and to gain some form and consistency in this format.
"It's an important year for us with the ICC Champions Trophy in June and regaining the No. 1 position is a step in the right direction for our preparation ahead of the event. It's a tight contest at the top so it'll be important for us to continue putting in the performances so that we can hold onto the position."
South Africa last sat on top of the tree in November 2014 before India moved to the number-one position after defeating Sri Lanka by 5-0. Later that month, Australia claimed the coveted top spot after defeating South Africa 4-1.
This is the fifth time South Africa has surged to the top since the current rankings system was introduced in 2002. It enjoyed top positions in February 2007, March-May 2008, January-August 2009 and October-November 2014.
Since the 1 May 2016 annual update of the ICC ODI Team Rankings, South Africa has played 17 ODIs, winning 13, including 11 on the trot. Its three loses have been against the West Indies (two) and Australia (one), while one match ended in a no-result.
South Africa will now get a chance to create further daylight between it and Australia when it plays five ODIs against New Zealand from 19 February to 4 March. To retain the top spot, South Africa will have to win the series by 3-2 or better. If New Zealand wins by 3-2, then South Africa will slip behind Australia by a fraction of a point.
Meanwhile, Sri Lanka have dropped three points following its performance in South Africa. While it has stayed in sixth position on 98 points, its pre-series 10-point lead over Bangladesh has been reduced to seven points, with eighth-ranked Pakistan another two points behind.
England plus the 7 highest-ranked sides on the ICC ODI Team Rankings as on 30 September 2017 will qualify automatically for the ICC Cricket World Cup 2019.
The remaining four sides from the ODI table along with six sides from the ICC World Cricket League will feature in the ICC Cricket World Cup Qualifier 2018 to fight for the remaining two places in the pinnacle 50-over to be staged in the United Kingdom from 30 May to 15 July.
ICC ODI Team Rankings (as on 10 February, after South Africa-Sri Lanka ODI series)
(Read as Rank, Team, Points)
1. South Africa 119
2. Australia 118
3. New Zealand 113
4. India 112
5. England 107
6. Sri Lanka 98 (-3)
7. Bangladesh 91
8. Pakistan 89
9. West Indies 87
10. Afghanistan 52
11. Zimbabwe 47
12. Ireland 42