Lionel Messi has once again been the driving force behind Argentina's World Cup campaign. The 39-year-old is enjoying another remarkable tournament, leading the Golden Boot race with eight goals while finding the net in every match so far. He has also continued to add to his long list of records with almost every appearance. More importantly, Messi has delivered when Argentina have needed him most. He inspired the defending champions to escape difficult situations against Cape Verde and Egypt, producing decisive moments that kept their title defence alive. While a new generation of stars continues to emerge, Messi has once again shown why he remains the standard everyone is trying to reach, setting the pace in the Golden Boot race and proving he can still decide the biggest matches on football's grandest stage.Lionel Messi is leading the Golden Boot race. (AP Photo)Messi's performances have drawn admiration from across the football world, including Barcelona teenager Lamine Yamal, who admitted he has been amazed by the Argentina captain's level at 39. Yamal said everyone knows Messi's greatness, but believes very few expected him to dominate the tournament in the way he has.Speaking to a Spanish outlet, El Mundo Deportivo, as quoted by ESPN, Yamal said on Messi, "Incredible (on Messi's performances this tournament). Everyone knows who Messi is, but no one expected him to be playing at such a high level. I am really happy for him."Also Read - 'Doesn't get better than to play vs Lionel Messi': Switzerland send respectful warning before Argentina clash“I am not satisfied with what I do”: Lamine YamalMeanwhile, talking about his World Cup campaign so far, Yamal believes he still has another level to reach. The teenager admitted he is continuing to regain rhythm after spending nearly two months on the sidelines through injury and insisted he is his own biggest critic. Yamal said he expects his best football to come in the latter stages of the tournament as he builds match fitness and confidence."I had been out for almost two months, and it is not the same as when you have played seven games in a row. I need to keep touching the ball, keep playing, keep racking up minutes, and, obviously, that game will come," said the Spanish star."I think I can do better. I am very hard on myself. I am not satisfied with what I do. I have never been the best player in the group stage. I am not worried about that. I know I have opportunities to prove it. The closer the important matches get, the semifinals or the final, the better I play,' he added.