Last month, Anderson continued his slide out of the top 20, slipping from 21 to 22, but had regained a place this week.
The 27-year-old, who has a career best ranking of 19, has not taken part in a tournament since falling out of the Australian Open in the fourth round in January.
South Africa’s next best male competitor, Rik de Voest, slipped three places and found himself 174th in the standings.
Men’s doubles star Raven Klaasen, fresh off of a win in the National Indoor Championships in Memphis, US, with partner Eric Butorac, stayed in 30th place in the doubles rankings.
In the women’s section, Charni Scheepers stayed put in 78th position, while Chanel Simmonds dropped seven places from 220th to 227th.
Scheepers also remained unmoved in the doubles rankings, staying at number 50.
The biggest climber among the women was Natasha Fourouclas, who rose an impressive 53 spots from 716th, to 663rd.
Lucas Sithole remains South Africa’s top-ranked wheelchair tennis player, but was unmoved in second position in the world rankings.