The Spaniard was outraged when referee Nicola Rizzoli was tricked by Young's dive and awarded the penalty which Robin van Persie smashed against the post during Manchester United's Champions League goalless draw with Sociedad.
Bergara told The Sun: 'I barely touched him and he dived. The truth is that he cheated.
'I can't describe the anger at that moment. We could have lost because Young cheated.'
Speaking of Young's reputation, Bergara added: 'I know all about the criticism against Young in England.
'We know that in England these things are considered very bad and I think the incident is clear to see on TV.
'He just brushed against me and fell to the ground.'
The former Spain Under-20 midfielder will now be banned for Sociedad's penultimate Group A match against Shaktar Donetsk as he cannot appeal the yellow card he received.
'I am sad and angry because not only was it not a foul but also I was given a yellow card and I can't play the next game. It's a double injustice.'