Rostov manager Ivan Daniliants has claimed that Manchester United may find it tough to adapt in Thursday's Europa League tie due to the poor quality of the Olimp-2 playing surface.
UEFA has already confirmed that the teams will train at a nearby training ground rather than at the Olimp-2 in an attempt to avoid causing further damage to the turf.
Daniliants has told opposite number Mourinho that the conditions are the same for both teams, though, as Rostov look to pull off a major upset on home soil.
"The pitch is the same for everyone, but it will still be a problem," he told reporters. "In the final of the League Cup, United played on an ideal lawn - it was like a carpet. When they arrive here, they will be surprised."
Rostov, 3-2 winners over Bayern Munich in the Champions League earlier this season, have never previously faced an English side in European competition