La Roja must not lose against les Bleus to retain a realistic chance of finishing top of Group I, and thereby avoid having to go through the playoff process to secure a place in the World Cup 2014 finals.
Benzema has not scored for France since June last year and Arsenal defender Monreal is keeping his fingers crossed that this continues, but insists if his Gunners teammate Olivier Giroud plays then Spain will be equally prepared.
"I hope [Benzema] continues to go another game without scoring and has a bad day against us, because he is a great player, and if you give him the slightest amount of space, he can score," he told reporters on Sunday. "Benzema and Giroud are both very important players for France. We know Giroud well, he is very strong and has an eye for goal. But regardless of who plays, we will have to be very focused."
Monreal could start against Didier Deschamps' men due to first-choice left back Jordi Alba picking up a knock in the 1-1 draw with Finland on Friday, and he revealed he has been working tirelessly to prove himself to head coach Vicente del Bosque.
"This is a very important match," he continued. "You would guess that, due to Jordi's injury, I will play, but we don't know who's going to play yet. I have been training hard so I can give my all if I do get the chance, because a lot is at stake in this game.
"We know that we have to go out to beat France by whatever way possible because we are the world champions. And after two draws in a row, the obligation to win is even greater."
A defeat to France on Friday would leave the Euro 2012 winners five points adrift of the Group I table topper with three games to go, and the former Malaga fullback admitted that mistakes must be eliminated from the team's game.
"There is no margin for error," Monreal added. "If we lose we will be five points behind France. We have to win so that our fate is in our own hands, like it is right now."