Earlier in the season, the 24-year-old spent a period on the sidelines with a muscular injury.
However, he recently returned to action and went on to score twice against Oxford at the R Costings Abbey Stadium.
"I was trying so hard to get three, believe me. It just wasn't quite meant to be, but I'm happy with the two nevertheless and a great team performance," he told the Cambridge Evening News.
"I was injured for a little while so I've been working hard on my fitness and obviously it showed out there on Saturday. I've been putting the work in in training and kept going and the consistency has come through in the end."
Appiah joined Cambridge on a six-month loan deal from Crystal Palace in the summer.