Johannesburg – South Africa's Kevin Anderson dropped two places to 17th in the latest ATP world rankings.
Despite reaching the semi-finals of the Mexican Open on Friday, where he lost to Kei Nishikori.
Anderson broke a run of five weeks unchanged at 15th in the world to slip down to 17th, his lowest ranking since the end of October last year.
Meanwhile, the country's top-ranked doubles player, Raven Klaasen, kept his place at 29.
South Africa's top-ranked women's player, Chani Scheepers, continued to fall down the rankings list, slipping five spots to 93rd in the world. – Sapa