Rafael Nadal insists tennis is a "very clean sport" but has called on governing bodies to make doping tests transparent.
The seven-time French Open champion came from a set down to defeat Daniel Brands in his opening-round encounter at Roland Garros on Monday, however his post-match press conference was dominated by the topic of doping.
"If you make the controls public and everybody can know how many controls that everybody has, then you are not going to have these questions because you will know how many controls we will have. That's my feeling," Nadal said.
Along with fellow professionals Andy Murray and Roger Federer, the Spaniard was dismayed by the Spanish courts decision to destroy 211 blood bags at the end of Operación Puerto in April.
Nadal has won the last seven French Opens he has competed in
Dr Eufemiano Fuentes was convicted over his role in supplying blood transfusions to sportsmen, which also included footballers, runners and tennis players, yet their identities were protected by the court.
Nadal stated transparency was essential.
"So why can we not make everything clean? Why can we not make everything public? Then we don't have to come here and ask if we are overtested or, you know, we are not tested enough," Nadal added.
"That's my feeling. Tennis is a very clean sport. We don't have a lot of cases of doping. And we are having a lot of controls."