When Young went to ground under a challenge from Villa defender Ciaran Clark, Halsey had no hesitation in pointing to the spot. Villa players were incensed by the decision and argued the Reds winger had made the most out of minimal contact. It's been a hot topic for debate in newspapers and on television ever since.
Sir Alex acknowledged at the time that Young, a player who arrived at Old Trafford last summer from Aston Villa, "overdid it" and took "a dramatic fall". But he was also insistent that Clark had committed a foul - a view he reiterated at his press conference on Friday morning.
"If [Clark] doesn't bring him down Ashley's going to score," he said. "It was a clear goalscoring opportunity and he did catch him.
"I'm not sure Ashley tried to get the penalty kick but he certainly went down quickly. I've had a word with Ashley and he understands where we're coming from. Hopefully it makes a difference."
The Reds boss went on to bemoan the way diving - or "simulation" to give it its technical term - has infiltrated football at all levels and believes the furore currently engulfing Ashley Young is purely down to his status as a Manchester United player.
"I watched Real Madrid v Bayern Munich and it was absolutely ridiculous. Players diving, rolling about... [far worse than] what Young's been accused of and the way the press have reacted because it's Manchester United. There's no doubt about that.