Young extended his leg in front of approaching defender Georgi Shchennikov and tumbled to the ground before any contact was made in the game. He escaped any punishment from the officials for his antics.
"If he's a Manchester United player, I'm a Chinaman. It's absolutely disgraceful," Keane told ITV.
"The senior players need to get hold of him. That shouldn't be accepted at Manchester United.
"That's not leaving your leg in. That's different. It's the somersault he does, it's an absolute disgrace.
"Maybe once or twice can be seen as a mistake. But he's done it nine or 10 times and he's done it at his previous clubs."