Accusations of vanity are nothing new for Cristiano Ronaldo, but it seems during his Manchester United days he was happy to say he was better looking than Lionel Messi. 

In his new book, former England striker Peter Crouch (h/t the Mirror's Martin Domin) relayed stories told by Three Lions team-mate Rio Ferdinand about Ronaldo during his time at Old Trafford.

Ferdinand revealed Ronaldo's United team-mates used Lionel Messi to motivate him:

"Rio Ferdinand would tell us stories about how Cristiano Ronaldo would stand in front of the mirror naked, running his hand through his hair, and say, 'Wow. I'm so beautiful!'

"The other United players would try to wind him up [by saying] 'Whatever, Leo Messi is a better player than you.'

"He would shrug his shoulders and smile again. 'Ah yes. But Messi does not look like this.'"

It's unlikely the Juventus forward would entertain the idea of Messi—or any other player, for that matter—being better than him these days.

Ronaldo left little doubt as to where he places himself in the pantheon of football's greatest after he won his fifth Ballon d'Or last year:

Such comments don't always ingratiate him to those who prefer a touch more humility in their superstars, like Goal's Robin Bairner, but as former footballer and writer Justin Bryant noted, his self-obsession has helped propel him to the pinnacle of the sport:

There's no doubting the phenomenal amount of work the 33-year-old has put in at every step of his career to not only achieve success but sustain it, which has seen him rival Messi at the top of the game for the last decade.

Privately, Ronaldo may wish he and Messi did not play at the same time, as in almost any other era his status as the world's best would be virtually disputable. 

However, striving to equal or surpass the Barcelona star may have given him an extra source of motivation throughout his career—if Messi weren't around, it's possible Ronaldo would not quite have hit the extraordinary heights he has.