Johannesburg - South Africa's top-ranked tennis players moved in opposite directions when the latest men's and women's world rankings were released on Monday.
Kevin Anderson fell five places to 33rd in the men's list after reaching a career high two weeks earlier, while Chani Scheepers climbed two positions to 40th in the women's rankings.
Both players reached the third round of the Sony Ericsson Open in Miami, Florida, which concluded at the weekend.
After a bye in the first round, Anderson defeated Sam Querrey of the United States before he went down in straight sets against another American, former world No 7 Mardy Fish.
Scheepers fought back from a set down in both her first-round matches, securing victories over Romanian Irina-Camelia Begu and Spaniard Anabel Medina Garrigues.
She took Australian Samantha Stosur to three sets in the third round, but was ultimately eliminated by the world No 5.
Scheepers, meanwhile, went down 1-6, 6-1, 4-6 against Argentine qualifier Paula Ormaechea in the first round of the Family Circle Cup in Charleston, South Carolina, on Monday night.
Anderson has the week off, having made himself unavailable for the Davis Cup tie against Slovenia, starting in Soweto on Friday, after facing difficulties in securing a visa while he attempts to qualify for his US Green Card.