Cristiano Ronaldo's Portugal teammate Manuel Fernandes has insisted that the Real Madrid attacker can "play at the highest level until he wants" to retire.
Ronaldo's performances in the early stages of the 2017-18 campaign were called into question, but the 33-year-old has been in impressive form in recent weeks.
Indeed, the attacker has now managed 28 goals in 31 games in all competitions for Madrid this season.
Fernandes, who plays his club football for Russian side Lokomotiv Moscow, has said that Ronaldo is not even close to hanging up his boots.
"Cristiano is special because of his strong winning mentality," Fernandes told Omnisport. "He is very aware of what needs to be done in order to achieve his goals.
"Obviously, he takes care of himself and that's another main reason for his success. A true model of professionalism and constant superiority. Keeping up his physical condition and wanting to achieve more, he can play at the highest level until he wants to."
Ronaldo has scored 14 times in 20 La Liga matches this season, while he has managed 11 goals in seven Champions League fixtures.