Tottenham Hotspur boss Mauricio Pochettino has revealed how he transformed star striker Harry Kane from a frustrated figure who doubted his future at Spurs to one now considered one of the world's best.
The Argentine arrived at White Hart Lane in the summer of 2014, fresh off the back of the north Londoners sixth-place finish - 15 points behind eventual champions Manchester City.
The 45-year-old was chosen following an impressive 18-month tenure at Southampton, who had concluded their campaign just two places behind the Lilywhites.
When Pochettino arrived at the club Tottenham held the worst defensive record out of the top eight sides and had scored 47 times less than trophy-winners City.
However, unbeknown to most, on arrival to White Hart Lane the former centre-back would discover one of the hottest properties in the world of football today, Kane.
"Kane was a frustrated guy when I arrived", the Spurs boss told Guillem Balague in his new book Brave New World, as cited by the Daily Mail.
"He struggled to visualise his future at the club, with two or three strikers ahead of him. He was constantly being shipped out on loan. It was doubly exasperating for him as a Tottenham fan.
"The club then suddenly hired an Argentinian coach and I picked up on his sense of resignation: ‘I’m sure this guy will bring in some other big-name striker.’
"It was a tough few months because we didn’t click initially. He was out of form and, at 21, had the habits of a player in his thirties, the type who has been around the block."
However, Pochettino was not one to abandon the obviously talented youngster, and took it upon himself to nurture the England international into the talent he is today.
"I had several stern conversations with Harry in which I had to make him understand that he had to get ready for whenever the opportunity might arise", the Tottenham manager said.
"Fame and a hefty transfer fee don’t pave the way to a starting berth, only hard work.
"Harry was humble enough to listen and take advice. We put the tools in place for him to improve.
"The moment finally arrived for him. He played and then played again. By seeing his progress the boys coming up through the ranks realised that we kept our word."
Since that point Kane has not looked back, and is now regarded as one of the best strikers in the world.
The 24-year-old has netted 18 goals for club and country so far this season in the same amount of games, and Pochettino believes his star man is now truly 'elite'.
"Kane is a warrior now", the Argentine added.
"He already was, but he didn’t know he had it in him. I’m not speaking about qualities or traits, but that essential mental strength to be able to stay in the elite. I believe he is the best player in the world in terms of mental strength, willpower and endeavour.
"He is completely focused on his football. He has a house in Essex but spends the week at another one he owns closer to the training ground.
"He’s the first to arrive and the last to leave. He likes to join in when someone with different experiences in football visits. He enjoys sitting down with us, soaking it all up and participating in the discussions.
"At those times it is as though for him nothing else in the world exists.
"And, at 23, [when the diary was written, he is now 24] he is as enthusiastic as ever: he enjoys training, he prolongs his sessions and he studies elite players, past and present.
"I WhatsApp him videos of goals or interesting pieces of play by other strikers. At all hours. The last one I sent was at 11pm."