The Ghana international, who has spent his entire career so far in the English lower divisions, saw 90 minutes of action as The Royals succumbed to a 2-0 defeat in the third round fixture.
Despite the result, the privilege of playing against the Red Devils at their renowned home ground has left some delight in the heart of the 27-year-old.
"We came out here and we just wanted to express ourselves and do what the manager's been telling us to do," Yiadom said, as reported by his club's official website.
"Despite the result, I think we went out here and we did that.
"You could tell everyone wanted the ball and wanted to express themselves and show what they could do.
"It's a lovely stadium, it was kind of like a day out for us but, at the same time, we all wanted the result because we had confidence in ourselves - especially with the way the first half started.
"It was my first time here at 27, it was nice to come here and it's one for the grandchildren."
Yiadom joined Reading from Barnsley in the summer following the latter's relegation from the English Championship.
He was also once on the books of lower division sides Barnet, Braintree Town, and Hayes & Yeading FC.