The win marked the 150th anniversary of Aston Villa's founding.
Onana later told VillaTV: “It was really special. That’s the right way to celebrate it for the fans. I think we needed a win.
“They came tonight supporting us, giving us the extra cheer we needed, so I’m really grateful for that.
“It was very special because I’ve never scored at Villa Park so far.
“The last couple of weeks for me have been very frustrating. I’ve been out with my injury for four or five weeks, then I came back, started enjoying it, then I had the flu, went back out the team.
“I really needed this energy and the goal. The little stare (celebration) was to let them (Villa fans) know I’m back!
“That’s the part of my game that was missing a little bit last season, and I’m trying to add more goals to my game.”
He also said of the 2-0 win: “The first half, they were very, very compact.
“They didn’t let any balls through the middle, so it was quite hard for me and Youri (Tielemans).
“But then at half-time, the gaffer made a couple of tactical changes, took Bouba (Kamara) on the side to play a little free, to create an overload on the side.
“Once we got there, we did pretty well, so I’m very happy with the performance tonight.
“Coming in was really difficult because I didn’t have any warming up. I didn’t even see Ross (Barkley) getting injured.
“I managed to find my rhythm throughout the game and I’m quite happy with it tonight.”