Part of complete coverage on
Roger Federer demands more drugs testing as debate rages at ATP finale
November 8, 2013 -- Updated 2048 GMT (0448 HKT)
Roger Federer voiced strong opinions on the lack of drugs testing at the top level of tennis.
- Roger Federer wants more drugs testing in tennis
- Reacting to the debate over Viktor Troicki's punishment
- Federer beats Richard Gasquet at ATP World Tour Finals
- Novak Djokovic into semifinals after beating Juan Martin Del Potro
(CNN) -- Roger Federer kept his hopes alive at the ATP World Tour Finals Thursday with a straight sets win over Richard Gasquet then repeated his demand for more rigorous doping controls in tennis.
"I just feel like we're not getting maybe tested enough," said Federer after completing a 6-4 6-3 win over his French opponent.
"I 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.
"Also last year when I won Dubai, Rotterdam and Indian Wells, and the year before that, I didn't get tested in one of those three events that I won. For me, that's not okay.
Read: Serb stars slam anti-doping system
Federer: Do more drug testing
Roger Federer: You can't always win
Roger Federer: A crusader for education
"You show up and test a guy that's winning everything. That's sometimes what I struggle with.
"But overall I trust the system. I think they're all very professional," the 17-time grand slam champion told gathered reporters.
Drug testing has been a hot topic all week at the end of season showpiece in London, with World No.2 Novak Djokovic mounting an outspoken defense of his Serbian colleague Viktor Troicki and saying he had lost faith in the anti-doping regime.
By contrast, Federer said he had little sympathy for Troicki, who saw his original ban cut from 18 months to 12 months Tuesday.
Troicki failed to provide a blood sample after feeling unwell at the Monte Carlo Masters but claimed he had been given permission by the doping control doctor to come back the next day.
"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," Federer said.
Read: Djokovic battles past Federer
"Like the test the next day for me is not a test any more because of what could have happened overnight.
"I believe whatever they decided on. I think it's just very important to give the sample when you're requested to give it because there you are in front of them and there is no way to escape. That's where we just need to be extremely firm."
Djokovic later beat Juan Martin Del Potro 6-3 3-6 6-3 in another tight three set match at the O2 Arena to book his passage into the semifinals.
It was his 19th straight win since losing to Rafael Nadal in the final of the U.S. Open and kept him on course in his title defense in London.
Defeat for Del Potro also boosted Federer's hopes of reaching the last four in a tournament he has won six times.
He will now meet the Argentine in a winner takes all final Group B match Saturday.
Today's five most popular stories
Part of complete coverage on
September 11, 2014 -- Updated 1248 GMT (2048 HKT)
His distinctive crocodile logo is seen on clothing all over the world, but Rene Lacoste also left a lasting legacy in the development of tennis.
September 9, 2014 -- Updated 0636 GMT (1436 HKT)
Marin Cilic follows in the footsteps of his coach Goran Ivanicevic by claiming a grand slam crown for Croatia, winning the U.S. Open.
September 14, 2014 -- Updated 1334 GMT (2134 HKT)
Serena Williams is without peer in the modern women's game and now she is on a par with two American tennis legends from the past.
September 2, 2014 -- Updated 1321 GMT (2121 HKT)
Over the course of her remarkable life, Althea Gibson was many things to many people -- but it was tennis where she really left her mark.
August 27, 2014 -- Updated 1145 GMT (1945 HKT)
Canada and tennis? Really? Yup. The North American tennis power balance is swinging away from the States.
August 21, 2014 -- Updated 1252 GMT (2052 HKT)
As a player he was as fiery as his hair -- and as Novak Djokovic's coach, Boris Becker says he has to battle to keep his emotions in check.
August 20, 2014 -- Updated 1102 GMT (1902 HKT)
Tennis great Boris Becker says he was stunned by the level of criticism he received after being appointed as Novak Djokovic's coach.
July 25, 2014 -- Updated 1101 GMT (1901 HKT)
"I didn't cry once when I practiced in front of the mirror," says Martin Emmrich. But the nerves kicked in when he got down on one knee on court.
June 30, 2014 -- Updated 1135 GMT (1935 HKT)
When Agnieszka Radwanska refused to look her opponent in the eye after losing at Wimbledon, it raised more than eyebrows.
June 23, 2014 -- Updated 0114 GMT (0914 HKT)
It's 10 years since a teenage Maria Sharapova became the darling of Wimbledon's hallowed Center Court, launching herself as a star.
May 23, 2014 -- Updated 0746 GMT (1546 HKT)
He's regularly voted France's favorite famous person, but many of the nation's youth have "no idea" about his glorious sporting past
April 29, 2014 -- Updated 1555 GMT (2355 HKT)
Five-time grand slam champion Martina Hingis has followed her mom into a coaching role, setting up a new tennis academy in Barcelona, Spain.