Harwood-Bellis struck a first goal for England in the 5-0 Nations League victory.
He later said, "It is a great day for me and my family. It's every young kid's dream to make their debut, and to score the goal is magical.
"I had a few hints yesterday that I would be needed at some point, when I got the nod to come on I was over the moon.
"There's always a pathway and us young ones, we do believe we can get into the seniors. We know the door is open if we take our chances, I've got to thank Lee (Carsley) for calling me up and I have repaid him with a nice goal.
"Playing for my country at every level is something I take such pride in. To play for the seniors is something you dream of, it is the pinnacle of football, to do it and score is some feeling."