The Red Devils appointed Mourinho as their new manager at the end of the 2015-16 season before the Manchester United boss brought in four new players to revamp the club's squad.
"I don't know which team I will play, I don't know if Mkhitaryan is going to play", he added. "I know we have to but it is hard to believe we are playing on that field if you call it a field", said the Portuguese.
"No reaction, he plays tomorrow", he said. "The next game will be in Manchester and, there, I think United will win".
It's often hard to agree with some of Mourinho's complaints, but in this case, he's fully justified.
"I have just been outside and the pitch is not the best", he said. But it looks like we have to play.' Uefa have since confirmed there is no chance the match will be called off.
Jose Mourinho needs to make three big-name Manchester United signings in the summer transfer window, according to David May.
'Maybe the quality of the game will be a bit different, but it doesn't have to be an excuse for us.
"The pitch is not good, maybe for safety as well".
The powerful Swede has already been penciled in to start for United in Russian Federation ahead of a three-match domestic ban; served by the FA after the striker chose not to contest a violent conduct charge for elbowing Bournemouth's Tyrone Mings.
Rostov - last season's Russian league runners-up - sent a clear warning to Mourinho's men when they routed Tomsk 6-0 on Friday.
The Belgium worldwide, who was sparingly used by former Red Devils boss Louis van Gaal in the 2015/16 season, received a new lease of life after Mourinho took charge of the club last summer.
However, despite the pitch, if United play to their best they should return to Old Trafford with at least a draw, which would set them up well to advance after the home leg.