Roger Federer has called for more drug testing in tennis following the controversy over Viktor Troicki's 12-month ban.
Novak Djokovic recently hit out at the anti-doping authorities after the Court of Arbitration for Sport reduced the ban of his fellow Serbian, who missed a blood test, but did not overturn it.
The decision prompted Djokovic to say that he had lost his faith in the sport's anti-doping programme but Federer stated that "overall" he trusts the system.
And the 17-time grand slam champion, speaking after his Group A win over Richard Gasquet at the ATP World Tour Finals, even called for the number of anti-doping controls to be increased.
"Honestly I don't talk a whole lot with the other players about it," Federer said when asked whether Djokovic's view represented the players as a whole.
"I just feel like we're not getting tested enough. I didn't get tested in Basel, I don't think. I didn't get tested in Paris, I don't think. I got tested here after the first match.
"I just feel like I used to get tested more. I think I was tested 25 times in 2003, 2004. Ever since, I think it's been clearly going down.
"This season, because I haven't been playing so well, I maybe missed those days when (they tested).
"Also last year when I was on that run, (winning) Dubai, Rotterdam and Indian Wells, I didn't get tested in one of those three events that I won. For me, that's not OK."
Although Federer stressed he did not know what was said during the conversation between Troicki and the doping control officer, the Swiss player believes a sample should always be given when requested.
He added: "I do believe that when you are requested for a sample, you have to give the sample.
"It doesn't matter how bad you feel, I'm sorry. For me the test the next day is not a test anymore, because what could have happened overnight?"
As for his victory over Gasquet, Federer was pleased to get his campaign back on track following an opening loss to Djokovic in the group.
"Richard does a good job of making you feel uncomfortable at the same time as well because he uses height and spins really well. He likes extended rallies. I'm trying to force the issue.
"But I guess those are the kind of matches I need right now - straight sets against a good player. It clearly comes at the right time."
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