The 22-year-old, who started his career at the Welsh club before joining the Gunners in 2008, scored twice at the Cardiff City Stadium and was applauded by the home supporters on both occasions.
"It was one of those moments that I will never forget," he told Sky Sports News. "It was a really nice feeling for me. Even though I didn't show that I was too happy with the goal, everybody else in the stadium showed their appreciation for it.
"I was delighted with the reception and the way they reacted to when I did score. It was a nice feeling for me personally, having a great reception like I got today.
"Hopefully I gave something back to them with the performance that I showed today - this is where it all started for me and they helped me on my journey to become the player that I am today. I hope they realise that and I gave them my respect as well by not celebrating my goals."