Powell was given his first coaching role by Foxes boss Nigel Pearson, but was not the only former Leicester man to make an impact on the night as Yann Kermorgant returned to haunt his previous employers - scoring the first then setting up Danny Haynes for a spectacular 20-yard winner after Chris Wood had equalised.
"I've done the double over Leicester and my mentor and I don't know how to feel really," said Powell. "I'm pleased for my club and pleased for my group of players. We needed a result and they were made to work hard for it.
"It's huge because we had lost three games and drawn one in our last four. We've been playing well but we've just been getting hurt by late goals and a poor goal conceded at Hull on Saturday. It's fallen for us this evening.
"I'm really pleased for my players because they believe in themselves, I trust them immensely, they work really hard. You just hope that they can continue to build on that and we're just looking for consistency. I hope this is the start of a really good run for us."
Kermorgant's ill-fated spell with the Foxes is best remembered for his missed penalty in the play-off semi-final defeat to Cardiff two years ago, when he chipped the ball straight to Bluebirds' keeper David Marshall.
However, Powell praised the 31-year-old's display on his first return to Leicester since then, and feels the time has come for everyone to move on.
"I played it down with him," added Powell. "I thought he was immense. He led the line on his own, won numerous headers, took his goal very well. He played the game I'd like from him every week - I might have to tell him we are playing Leicester home and away every week."
Pearson said: "It's a disappointing result. I think they came to do a bit of a job on us and they did it well in terms of getting everybody behind the ball and limiting our ability to play the type of football that we do.
"When you concede the types of goals that we're conceding it gives us a problem in terms of winning games and that's really the top and bottom of it. I don't think we deserved to lose the game but we have. I know the second goal is a good strike but we've not dealt with a situation I'd expect us to snuff out. From a defensive point of view it's certainly avoidable."