Moscow cold and plastic pitch worry Mourinho
"Minus 10 [degrees Celsius] outside is not the same as a plus 15," Mourinho told reporters in reference to the sub-zero temperatures in the Russian capital.
"Then you must play on a plastic pitch, which is not easy, especially in cold weather."
The outspoken Portuguese expressed his dislike for the Luzhniki's synthetic surface on his previous visit to Moscow with Inter Milan two years ago, saying football was "much more beautiful when it is played on a natural grass."
"Nevertheless, we expect to get a positive result tomorrow, either a win or a scoring draw," Mourinho said on Monday.
"The main thing for us is to get the aggregate victory and reach the quarter-finals."
Mourinho also intends to field his strongest team on Tuesday.
"I don't think I will rest a player just because of the cold or the plastic pitch," he said. "We have a strong squad, all players are of the same top level and I will make my selection based on the opposite team and not on the outside factors."
Real's Portuguese defender Fabio Coentrao said his team will have to overcome strong opponents as well as the elements.
"Of course, the cold would make the game much tougher for us. But it's not just the cold we must worry about," he said.
"[CSKA] are a strong team, they are used to the cold weather, familiar with the pitch, so it's going to be tough."
Coentrao and his team-mates will be relieved to know that mild temperatures of around zero degrees are forecast for Tuesday's game.