Villa have slipped, with Unai Emery's team now five points away from the top four.
Onana said, “We’ve just got to try and be better, myself first, just try and get as many points as we can. We saw it last week, we can do it against big teams.
“I’m very excited for the game against Brighton at home.”
Reflecting on defeat at Newcastle on Boxing Day, he also stated: “It was one of those days when you just have to try and forget it as quickly as you can and focus on the next one.
“I think playing for an hour with 10 men against Newcastle away, it was never going to be easy.
“I think the way we fought until the end, I don’t think anyone abandoned before the final whistle.
“We stuck together as a team, tried to do as good as we could and I’m proud of the team for showing that mentality.”