In the eyes of many, Lionel Messi is the greatest footballer of all time.
The Barcelona captain has rewritten the record books throughout his illustrious career, combining goalscoring and creativity like no other player in history has.
Pep Guardiola was a key man in turning Messi from a world-class player into an all-time great, the Argentine playing arguably his best football during the four years he spent under the Spaniard's leadership.
From the start of the 2008/09 season to the end of the 2011/12 campaign - the period Guardiola was in charge - Messi scored an astonishing 211 goals in all competitions for Barcelona.
The numbers almost beggar belief and according to the current Manchester City manager, the six-time Ballon d'Or winner was just as prolific in training.
In fact, Guardiola has stated that Messi never lost a single game on the Barcelona training ground during their four years together in Catalonia.
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"He's very strong, the strongest. Beyond his quality, it's his mentality, his head," Guardiola said on a Twitch live chat with former footballers Antonio Cassano, Daniele Adani and Christian Vieri, per Marca.
"In four years at Barcelona, we played a lot of games in training and he didn't lose even one. If he had lost, he would've left.
"He has that competitive mentality that only four or five players in history have, they have something different.
"We all knew that Messi was the best, but then there were six or seven others who were strong and others who didn't play because the others were so strong."
Messi might possess more natural footballing talent that anyone else on the planet, but he's still had to work mighty hard to achieve all he has in the sport.
The Argentine's eternal rival Cristiano Ronaldo is regularly lauded for his 'elite mentality' and while the Juventus star is deserving of that, Messi should be praised in the same manner.
(Credit: The Football Terrace)