Russia's World Cup team doctor claimed on Monday that his country's domestic football leagues were cleaner than any other sport on the planet.
Doping allegations have dogged Russia as it prepares to host the World Cup for the first time in mid-June.
Russian athletes were forced to take part in the Pyeongchang Winter Games under a neutral Olympic flag because of cheating at the 2014 event in Sochi.
Former Russian Football Union (RFU) chief Vitaly Mutko oversaw national preparations for the 2014 Games.
He became closely associated with the scandal and stepped away from World Cup preparations in December.
Yet Russian team doctor Eduard Bezuglov said there were simply no grounds for suspicion against players because they have all been clean for years.
He explained that the RFU and the Russian Anti-Doping Agency (RUSADA) were holding "mandatory online courses" and publishing medical guidelines for teams in all football leagues.
"There is no such thing anywhere else in the world," Bezuglov told the RIA Novosti state news agency.
"In other words, I do not know of any other sport that does not have a problem with banned drugs. But Russian football does not have this problem."
The world football governing body FIFA is still investigation allegations about past or present violations in the Russian game.
The most serious charges against it have come from former Moscow sports lab boss Grigory Rodchenkov — viewed as a traitor by the Kremlin and living in hiding in the United States.
FIFA has thus far been unable to confirm Rodchenkov's claims that past Russian World Cup teams doped or that current national players were involved.
But it has sent him a list of 59 questions to which it has so far received no public reply.
Bezuglov said 1,500 Russian player samples have been tested abroad since the World Anti-Doping Agency stripped RUSADA of accreditation in November 2015.
"In this entire time, there has not been a single positive test," said the doctor.
"I think that a lot of the credit for this should go to Vitaly Mutko, no matter what people may think of him now," Bezuglov added.
"He constantly told us: have meetings, explain things, educate and scare them, do whatever you want, but make sure there is no doping in football."
The beautiful game is not among the sports closely associated with doping and past Russian problems should have no impact on the World Cup.
"No Russians will be involved in the implementation of the anti-doping programme and all analysis of doping samples will be done at WADA laboratories outside Russia," a FIFA spokesman told AFP.
FIFA said the same was the case during the last tournament in Brazil because its laboratory also lacked certification at the time.
Updated Date: Mar 19, 2018 18:55 PM