Club director Sean Jarvis took to twitter to share the letter from young fan Adam Bhana, in which he asked the club if they would pass the money on to Mooy after his impressive performance against the 'Red Devils'.
The letter read: "I was at the Huddersfield against Manchester United match.
"I found a five pound note at the stadium and gave it to dad because you cannot keep what is not yours.
"Can you please ask (manager) Mr (David) Wagner, if Aaron Mooy can keep the money because he played very well and scored yesterday. I have put the five pounds in the envelope. Thank you."
Mooy scored the opening goal of the game before Laurent Depoitre sealed the points for the 'Terriers' just five minutes later.
I would love to meet you Adam
— Aaron Mooy (@AaronMooy) 24 October 2017