Fifa has refused to reveal how many drugs tests it has conducted on Russia’s World Cup squad following their staggering start to the tournament.

The game’s governing body would also not disclose whether any had taken place beyond those post-match amid a call from one of sport’s most senior anti-doping officials for it to publish details of each one carried out at football’s flagship event.

That came from the chief executive of the United States Anti-Doping Agency, Travis Tygart, who also said Russia must be aggressively tested to safeguard public confidence in the integrity of the World Cup.

Even before a ball was kicked at the tournament, Fifa was under pressure to ensure it did not witness a repeat of sport’s worst doping scandal - in which Russia covered up thousands of positive tests in and around the Sochi Winter Olympics - pressure the performance of its national team has only compounded.

Just days after being branded the worst side ever to stage the World Cup, Stanislav Cherchesov’s men produced the best start by a host nation - and one of the best by any country.