Casemiro thinks Cristiano Ronaldo is happy at Real Madrid and hopes he will not have to play against the Portuguese superstar in the future.
Four-time Ballon d'Or winner Ronaldo is said to be considering his future in Madrid amid scrutiny over his tax affairs from Spanish authorities.
The 32-year-old has refused to comment on the reports, instead focusing his attentions on the Confederations Cup campaign with Portugal, in which they finished third, and the birth of his twins.
Casemiro is confident he will stay at the Santiago Bernabeu, stating it would be tough to go up against another team with Ronaldo in their ranks.
"Of course, we want Cristiano to stay with us. He is the best in the world," said Casemiro.
"There is no explanation for what he has done for us.
"He is happy at Real Madrid and does not need to comment further.
"Playing against the best in the world is complicated, so I hope he does not leave."
Casemiro was speaking after being honoured in his hometown of Sao Jose dos Campos for his sporting achievements.
He praised the impact Zinedine Zidane has had on his career, the Frenchman making him an essential part of a team that has won two Champions League titles and La Liga.
Casemiro said: "Footballers are always learning new things. This year was the best of my career, but I am aware I need to keep growing and I want to continue growing with Real Madrid.
"For me it's a pleasure to be trained by Zidane. I am just very thankful for all he has been asking me to do and for helping me to evolve."