Andre Agassi has claimed that tennis is one of the world's cleanest sports in terms of drug abuse.
The spotlight in Sydney, Australia, has been on Greg Rusedski after the Briton's admission last week that he had tested positive for the banned steroid nandrolone.
But Agassi told reporters ahead of an invitational tournament that he is convinced tennis does not have a problem with doping.
"Well, one of the things we can say for sure is our sport is the leading, if not the top, sport in drug testing in both its intensity as far as what they test for," he said.
"It's a very extensive list, probably more extensive than any other sport, and how often they test. Last year I played 13 tournaments. I was tested (via a) urine sample 11 times, I was tested (via a) blood sample eight times, which includes three out of competition testings.
"It's not possible to get more aggressive with the goal of maintaining the integrity of our sport," he added.