Mourinho has penned a deal to 2016.
"I'm happy Mourinho stays on because he is the best coach in the world. He's given us things we lacked, and we improved and won the league title thanks to him," said Benzema, who also commented on his relationship with Zinedine Zidane.
"Zidane is like my older brother. I've been lucky enough to receive advice from the best French player in history."