Lionel Messi was in tears. It was March of 2008 and the Argentine had just played a one-two with Gianluca Zambrotta in Barcelona's Champions League clash at home to Celtic but pulled up in pain as he attempted to reach the Italian's return pass. He had torn a muscle in his left leg and would be out for six weeks. It was his seventh injury in the space of two years and the fourth in that particular place. A brilliant career appeared in danger and Barcelona, understandably, were worried.
But thanks to the incredible efforts behind the scenes at Barca, Messi has barely been sidelined since.
The summer of 2008 saw considerable change at the Catalan club. Pep Guardiola arrived as coach after a year with Barca B and a new project was born. On the pitch, Messi would be its leader. But with his injury record over the last few seasons, adjustments would be needed.
The first bold decision had been to dispense with the Brazilians: Deco and Ronaldinho were seen as problematic by the Barca hierarchy and it was feared their off-the-pitch partying would lead Messi astray. Under Frank Rijkaard, there had been a Brazilian clique at the club, but the two forwards - along with Edmilson, Thiago Motta, Julian Belletti and Sylvinho - had befriended their fellow South American. Messi was growing up fast - perhaps too fast.
With Deco and Ronaldinho out of the picture - and Sylvinho the only one of the Brazilians still left at the club, Messi was free from unwanted distractions. But he would have to change, too.
In his early years in Barcelona, Messi had taken comfort in Argentine food, savouring steaks at his favourite restaurant in the Catalan capital - Las Cuartetas. Visits were frequent and would involve a feast of both meat and sweets. Under Guardiola, that soon stopped. Leo had previously turned his nose up at vegetables and barely touched fish. Now, they formed part of his staple diet and, each morning, he would consume a special set of vitamins prepared and left for him in a small container at the club's training ground. Every player was handed a mixture of minerals to boost their very own needs. Nothing was being left to chance.
There would be no more late nights watching Argentine football, either, with Leo learning that sleep would speed up his recuperation and allow him to take his game to an even higher plane.
But there was still a concern that, at the tender age of 21, Messi could break down again. One more serious injury and his already fragile state may have suffered unnecessarily - not to mention his brittle body.
Guardiola therefore told Barca physio Juanjo Brau to watch Messi day and night. Brau shadowed Leo and the two have become inseparable, even sometimes seeing each other on their days off and travelling together when Messi plays for Argentina. In a new book, 'The Messi Mystery', authors Sebastian Fest and Alex Juillard explain his routine: "Before each training session, Leo trains with Brau, one on one, for 45 minutes and after each one he has another half-hour session.
"Messi stretches and relaxes his muscles and this physical maturity goes hand in hand with his football maturity: he has gained knowledge as a footballer, he is more intellectual on the field and has more control over his game."
That maturity extends to his free time but also to Messi's minutes on the pitch. Due to the explosive nature of his game, the Argentine has always been at risk with muscle injuries but with the help of Guardiola and Brau, learned to limit his work-rate in order to maximise his impact. Pep instructed his young star to stay upfield and conserve his energy for short, sharp bursts. He also improved his positional play and, with the help of Xavi and Andres Iniesta, he would have the ball when he wanted it - and when he needed it. So when he did, he was more effective than ever before and able to play 60 games per season because, despite his incredible influence, he now actually covers less ground than most of his team-mates. Less brawn, more brain.
"A lot of people help him daily, for example the physical trainers," Brau reveals in 'The Messi Mystery'. "The work we do with Leo is long term and we managed to consolidate him."
The physiotherapist goes on to describe the Argentine as a player of "unique explosiveness", but thanks to the wonderful work he has put in along with Guardiola and his coaching staff, as well as Leo himself, the Messi of 2012 is a very different player to the one who faced the Scottish side in 2008. Not only does the 25-year-old now have three Ballons d'Ors, but he doesn't get injured any more, either.
Alex Juillard spent several years working in Buenos Aires as a correspondent for L'Equipe; Sebastian Fest is Head of Sports in Spanish for German news agency dpa. Their new book, 'The Messi Mystery', was published in French earlier this year and will be out in Spanish and English in 2013