'You're the champion!' Cristiano Ronaldo's four-year-old son powers through a workout as they perform sit-ups

Cristiano Ronaldo has some competition - and it's not just from opponents on the football field.

The Real Madrid winger was surpassed in speed by his four-year-old son Cristiano Jr when they performed a workout routine together.

In a heartwarming video clip, the 30-year-old conceded to his mini-me who quickly completed a set of sit-ups, proclaiming: 'You're the champion!'

Real fit! Real Madrid star Cristiano Ronaldo performed sit-ups with his son Cristiano Jr in a heartwarming video cip

The sportsman began his exercise session with his boy, who helped Cristiano keep his balance by sitting on his feet.

However the little man grew weary of the task and opted to give his father more of a challenge - by adding resistance with his hands and head on his midsection.

Not able to fully complete his set with Cristiano Jr's restricting his movements, he ended at 16 sit-ups and decided to put the boy through the paces.

'I've done mine, so now it's your turn,' he said, adding, 'Just 10.'

Fast moves: He was surpassed in speed by his four-year-old son Cristiano Jr when they performed a workout routine together