Barcelona defender Gerard Pique has described Real Madrid's Cristiano Ronaldo as the "perfect machine" and praised the Portugal international for his desire to continually improve.
Ronaldo is favourite to win his second consecutive Ballon d'Or when the prestigious award is handed out in the New Year, and Pique has talked up the talents of the Portugal international.
He told Voetbal Magazine: "Cristiano is a perfect machine, a hard worker who always wants to improve. He is very demanding of himself, something that he showed at [Manchester] United.
"The most surprising thing is that [Lionel] Messi won four Ballons d'Or in a row and he kept going on there, with the strength to beat him.
"Many times conclusions are drawn based on specific actions without actually getting to know him. He has changed in recent years, I know him from United and he took to me well. He helped me a lot in Manchester."
Ronaldo moved to Real Madrid from Manchester United for around £80m in 2009.