Erik ten Hag hailed Manchester United's last-gasp hero Alejandro Garnacho - and then warned he is facing "danger".
Garnacho, at 18 years and 135 days, became the youngest player to score an injury-time winner in the Premier League since Federico Macheda in April 2009 when he was 17 years and 226 days.
Argentina wonderkid Garnacho did not make his nation's World Cup squad and Manchester United boss ten Hag admitted the break for the tournament will stop his momentum.
Ten Hag said: "It shows that he has the talent, a great talent but he has a long way to go. He has to make a big investment because it will be recognisable every time he plays.
"There's a four-week break now which is a danger for him because he now has the momentum. We will have to manage that but I’m certain we will.
"The danger is four weeks, no games. He needs to stay in the same attitude that he has shown in the last four or five weeks. He is fantastic. First, he shows the mentality you need. Under stress he's performing, he's coming in, he has an impact, he has the belief. Twice in three, four days, so that is really good.
"I'm really happy that we can bring a young player up and it shows that when players deserve it they get their chances. That is the first one but we have to bring more. He's great. I like that he has a big belief and that's great to work with. He likes football. He's a real pleasure.
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"If you want to be successful, want to win trophies, then you have to keep going and keep pushing until the end."
United boss ten Hag insisted that Cristiano Ronaldo should be fit for the World Cup despite missing a second successive game through illness. United have won eight of the ten Premier League games that Ronaldo has not started.
Ten Hag added: "He is ill, I don't think it's bad so we are confident (he will make World Cup)."
Fulham boss Marco Silva said: "It's really tough. A cruel game for us. The way we played, the way we performed, we deserved more from the game. This is the Premier League and if you lose focus then in one second they can punish you. This is the reality and you have to learn."
