Rio Ferdinand has heaped praise on former Manchester United teammate Cristiano Ronaldo.

As the Real Madrid star prepares for Portugal's opening game at Euro2016, Ferdinand took the opportunity to laud the 31-year-old who again scored more than 50 goals at club level last season.

"He's an unstoppable force," Ferdinand told Match of the Day magazine.

"Him and (Lionel) Messi are the two most productive players in the history of football – in terms of goals and their ratio!"

Ferdinand added: "Fifty-plus goals every year for the last six years is bananas.

"That doesn't come by taking your eye off the ball – it comes because you have your seat belt on all the time with your foot on the pedal!"