"Achilles is now in his place of work, he is preparing for the World Cup and going through the adaptation process", veterinarian Anna Kondratieva said during a training session at a pet shop near the museum.
Artem Dzuyba netted a third before terrific late efforts from Cheryshev and Aleksandr Golovin wrapped up Russia's first win since October to launch their Group A campaign in style.
Russian Federation kicked off their World Cup in style on Thursday, scoring early against Saudi Arabia in front of an ecstatic crowd in Moscow after President Vladimir Putin officially declared the tournament open.
"I am awed by their courage", he said in a statement.
"Little action has been taken by the Russian government and police to crack down on far right extremists who target LGBT+ people for violent and humiliating assaults - including the instigators of the current threats to bash and stab LGBT+ football fans at the World Cup".
Russia's win was also the biggest in a World Cup opener in 84 years since Italy's 7-1 over the United States in 1934.
British singer Robbie Williams performed hits including Feel and Angels in the opening ceremony as performers carrying glittering boards and others representing the countries at the championship fanned out around the pitch.
Warm-up losses to Italy, Germany and Peru have not made for the best preparations for the Saudis as they chase a first victory in the World Cup finals since 1994 in their first appearance in the showpiece event since 2006.
Russian Federation can now prepare to face Egypt next week full of confidence while Saudi Arabia need to find instant improvement if they are to avoid further embarrassment against Uruguay.
Russia's players were significantly taller and heavier than the Saudis, a help when challenging for the ball and when the penalty area was crowded. FIFA's most recent rankings put the Russian team in 70th, making it the worst-ranked team in the tournament and also marking the team's lowest-ever ranking.
Saudi Arabia had 60 percent of possession and played almost twice as many passes as their hosts, but were still blown away on opening day.
The heavy defeat leaves Saudi Arabia likely needing to beat Uruguay in their next match on Wednesday to stand a realistic chance of advancing beyond the group stage of the tournament.
But there was a major blow for the hosts mid-way through the half as star playmaker Dzagoev limped off with a hamstring injury, to be replaced by Cheryshev.