Former Manchester United coach Michael Clegg believes Real Madrid star Cristiano Ronaldo can play into his 40's.
Clegg worked with Ronaldo at United.
"If he's set in his mind, 'I want to beat him", he'll go for it," he told the Daily Mail. "The influences you have in your life will set so many standards for you.
"Ronaldo could play until he's 40. It all depends on how many people are gunning for him and if he gets injured it would cut it down.
"But work with Cristiano, as well as Ruud van Nistelrooy and Paul Scholes, was all about the brain. It's not about the brawn.
"You see the skills and the power but it's the brain. A multitude of things are happening, it's the players that can see everything then react to it that did the best."
