The two players have both won the Ballon d'Or five times and are widely regarded as the best two players in the world. Tevez says while Messi is a natural, Ronaldo has to work hard, per Goal's James Westwood:
"Lionel Messi, I never saw him in the gym. I've never seen him train to stop the ball or those exercises. It is all natural to him, but on penalties he trained: First he did not take them and now he shoots them all at the corner.
"Cristiano always stopped in the gym after training: For him it is an obsession, and being the best in everything, he always arrived at work early."
Both players have enjoyed hugely successful careers. Messi has won the UEFA Champions League four times and claimed nine La Liga titles during his time with Barcelona.
Ronaldo has won league titles and the Champions League with both Manchester United and Real Madrid. He also secured the 2016 UEFA European Championship with Portugal.
Although they have dominated European football, they remain two vastly different characters. Messi is at his best with the ball at his feet, driving forwards and dribbling past defenders.
He was the top scorer across Europe's big five leagues last season with 34 goals in La Liga. He also has a superb record when it comes to creating goals, as shown by Opta:
Messi tends to shy away from the spotlight, whereas Ronaldo is seen as more brash. He started off as a winger but has developed into a prolific forward.
The Portugal international scored 450 goals in 438 games during his time at the Santiago Bernabeu and is the club's record goalscorer, per Eurosport.
Ronaldo turned 33 in February but has shown few signs of slowing down as he heads towards the end of his career.
He left Real Madrid after nine years to join Juventus during the summer. The Serie A side were willing to spend €100 million (£88.3 million) on the forward, per Fabrizio Romano at the Guardian.
Ronaldo has endured a slow start to his career in Italy and is yet to score despite having a number of chances, as shown by Opta:
He has been shortlisted for The Best FIFA Men's Player Award along with Luka Modric and Mohamed Salah.
The decision not to include Messi was seen as a surprise. Atletico Madrid's Filipe Luis shared his view of what it meant for the award, per AFP's Tom Allnutt:
Messi's individual brilliance has become such a regular occurrence it appears to be the reason why he's been overlooked. Ronaldo's goals and success in the Champions League have caught the eye, and he could add yet another award to his vast collection.