Rafael Nadal withdrew from doubles at the Brazil Open to rest his sore left knee ahead of his opening singles.
Nadal will play Brazilian Joao Souza in singles on Thursday. Souza was leading Ruben Ramirez Hidalgo 7-6 (6) when the Spaniard retired because of a right ankle injury.
Nadal had won his doubles match with David Nalbandian on Tuesday.
Last week, Nadal reached the singles and doubles finals in Chile, his first tournament after being sidelined more than seven months because of knee the injury. He lost both finals.
Nadal says his knee is improving considerably, but adds there are days when it still bothers him.