Manchester United new boy Casemiro hopes Cristiano Ronaldo stays at Old Trafford as the Portuguese forward continues to be linked with a move away.
Casemiro was reunited with former Real Madrid team-mate Ronaldo when he completed a £60million (€70m) move to Old Trafford on Monday.
The Brazilian could make his United debut on Saturday when the Red Devils travel to Southampton in the Premier League.
Enforcer Casemiro is the fourth major arrival at United during the transfer window, but manager Erik ten Hag's first few months at the helm have been characterised by constant speculation regarding Ronaldo's future.
Ronaldo reportedly declared his intention to leave United after they missed out on Champions League qualification last season, but many potential suitors – including Bayern Munich and Atletico Madrid – have since ruled out signing the striker, who found the net 24 times in all competitions last term.
Ronaldo's future remains unclear with less than a week remaining in the transfer window, and he was dropped to the bench for United's 2-1 win over Liverpool on Monday – their first victory of the campaign.
Casemiro, however, is convinced of Ronaldo's continued importance, telling ESPN in Brazil: "The illusion of being able to play with him again ... he knows the respect I have for him.
"I hope he stays, because he is a player who gives you leadership, gives you many goals, is a winner and is very important to us.
"As we speak Portuguese too, we got closer. He was a guy who from the first day I arrived here, helped me a lot, gave me advice, is helping me a lot.
"He is a great player, one of the best of all time."
Having posted their lowest points tally (58) and worst defensive record (57 goals conceded) in their Premier League history last term, United will be featuring in the Europa League this season.
Casemiro, a five-time Champions League winner, is desperate to help United back into Europe's premier club competition, but he revealed the opportunity to play for one of the Premier League's biggest clubs was just as important in his considerations as he weighed up a move to United.
"I want to learn, United have always been very affectionate, from the first day, they made me feel comfortable," Casemiro said. "The coach was very attentive, charismatic from day one. They always showed interest. This is very important.
"The Champions League, of course, I want to win, if we don't play [in it], I'll be sad. I want to be there, even for the greatness of the club. But that happens with work and dedication.
"But the club has always shown a lot of affection, as well as Real. The feeling of being in a big club and being able to play in a big league like the Premier League, is very good and very important."