A look of disbelief flashed across the face of Lautaro Martinez. The referee had traced a rectangle in the air with his index fingers - the signal that his video assistant had been in touch over the radio - and reached into his pocket for a red card. The then 19-year-old, in one of the biggest games of his burgeoning career, was destined for an early bath. Martinez, despite the look of shock, knew what he had done. Moments before, whilst being pressured by England’s Fikayo Tomori, he swung out with a wild right elbow, nastily catching the Chelsea defender on the side of the head. It was an act of frustration. His Argentina team were 2-0 down in the opening game of the 2017 U20 World Cup and the young forward, after coming from the bench, was desperate to drag his side back into contention. Argentina would go on to lose the game 3-0, and, despite a Martinez brace in a 5-0 win over Guinea in the final group game, would not make it into the knockout rounds. Then, just weeks after being dumped out of that World Cup, Martinez broke a metatarsal in his right foot, adding injury to insult and keeping him out of Racing Club’s opening games in the 2017-18 Superliga Argentina. It was a tough period for him, but any up-and-comer will inevitably suffer disappointment and defeat at some point. The real litmus test is how they bounce back from it and, since his comeback, Martinez - now quicker and more muscular - has played like a man possessed. He scored on his return and has not stopped since, netting 12 times and notching three assists in just 16 games. Highlights have included a man-of-the-match performance away to Boca Juniors, in which he contributed a goal and a scintillating assist, a hat-trick against Huracan in the league and another three-goal haul in the Copa Libertadores against a hardy Cruzeiro defence. An array of European giants has been observing his development at Racing for some years already, but his performances over the past few months have pushed everyone into a state of red alert and Racing’s asking price to over €25 million.