If you're good enough, you're old enough. Adnan Januzaj may be just 19-years-old, but arguably he's been Manchester United's best player this season.
That's why many United fans were so shocked when they read that the youngster had been left out of the side's squad that took on Olympiacos on Tuesday night.
And that shock turned to anger and frustration as Red Devils fans watched their side humiliated 2-0 in Greece. David Moyes' side were truly awful and struggled to find away through their opposition with arguably their three most creative players out of the side.
Juan Mata was cup tied, Shinji Kagawa had to settle for a place on the bench and of course Januzaj was surprisingly left out of the squad altogether.
But why? In Manchester United's biggest game of the season so far, Januzaj had to play.
His presence seems to inspire his teammates, as he's been the one player to really stand up and be counted on a consistent basis this season.
I guess there is an argument to suggest that he needs protection. Phil Neville has just come out and said Manchester United must protect their prize asset and utilise him at the right time, but Tuesday night was the right time.
This is not a Manchester United team that can afford to over think their youngster's progression. This is a Manchester United team that need Januzaj in it.
As United go in search of Champions League qualification – which is looking increasingly unlikely – Januzaj must become a central figure for Moyes' side.
The United manager needs to give him more opportunities alongside the likes of Mata, Wayne Rooney, Robin van Persie and Co.
And with that second leg of the Champions League Round of 16 around the corner, it's vital Januzaj starts.
United will have to get off to a good start and Januzaj can provide that instant spark. Despite his age, he's ready to become a Manchester United superstar and must be made a key man at the Theatre of Dreams.