Benitez has seen enough of our opponents to understand the type of threat they will pose.
"At this stage of the competition every game is tough," Benitez told chelseafc.com. "They are a good team; they beat Atletico Madrid, and we know they are a strong team. They beat Levante, who are doing very well in La Liga, and they also finished ahead of Inter in the group stages.
"They are sixth in the Russian league, which isn't fantastic, but they have some good players. We know about [Ivan Sierra] Marcano and [Jose Salomon] Rondon, they are players who can make a difference, so it will be tough.
"The good thing is that we play the first leg at home. In another situation you would prefer to play the second leg at home, but in this case, because we have to play so many games, it could be good that we don't have to travel.
"We don't know yet where we will play. If it's in Moscow it will be a synthetic pitch, and if it's in Kazan it will be on natural grass, so we are waiting to hear."