The Cristiano Ronaldo versus Lionel Messi debate is one that will never have a definitive answer.
Each superstar has their own legion of loyal fans and the sheer volume of variables between the two players means picking a clear winner is nigh on impossible.
Does Ronaldo's prowess on the international stage elevate him above Messi? Or does the Argentine's assist record mean he simply has to be number one? You get what we mean.
But the variables haven't stopped players both past and present stating a case for one of Messi or Ronaldo being superior to the other.
The latest to follow this trend is Real Madrid legend Iker Casillas and unsurprisingly, the Spaniard has sided with his former teammate Ronaldo.
Casillas, 39, believes the Portuguese's success in the professional game is "more impressive" than Messi's, due to the fact that he's had to work hard to be the best.
“Cristiano always had huge desire to be the best, ever since he was a boy and I believe he has achieved that," Casillas told ESPN.
“If I have to compare him to Messi, what Cristiano has done is more impressive because we all know the talent Messi has, but Cristiano was determined and worked hard to be the best.
“I feel we have been lucky to have been able to enjoy two phenomenal players.
“For people that don't know Cristiano, he can appear to be cocky and arrogant, but it's totally the opposite.”
Casillas makes a valid point, as there isn't a player on the planet who's worked as hard as Ronaldo to get to the very top of the game.
However, Messi's own determination is often underrated. The Barcelona superstar keeps himself in tremendous physical shape and plays with a similar winning mentality as Ronaldo.
Both are as determined and talented as the other, which is why they will go down as the two greatest footballers of all time - by a country mile.