London - South Africa's chances of replacing England as Test cricket number one after their forthcoming three Test series became more difficult when the latest International Cricket Council rankings were published on Saturday.
The South Africans slipped to third in the list - Australia replacing them in second - and dropped to nine points off England from just a point adrift when the annual figures were issued.
The Proteas slipped down the list because their series victories in England and Australia four years ago were no longer valid to the rankings.
A 1-0 or 2-1 defeat to South Africa would see the victors go level on points with England, but above them by a decimal fraction.
Should England either draw or win, though, they will stay on top - and if they were to whitewash the tourists, South Africa would drop to fourth.
The first Test gets underway at The Oval next Thursday.