That left Wolves four points adrift of safety, but they responded by winning three of their next four to climb up to 12th at Christmas.
They have since won just one in eight, culminating in the 3-1 FA Cup reverse at Crystal Palace in midweek.
The Molineux outfit are back to just one place above the drop zone but Henry has pointed to the way Wolves bounced back from their previous derby setback for inspiration as they aim for Premier League survival.
"Our attitude has always been great but that was not a performance the gaffer expected," he told the Birmingham Mail. "It wasn't characteristic of us.
"We got our heads together after the Birmingham game, we had a few meetings and realised that we needed to do more and get back to the Wolves that we were.
"We have to prove that we can stay in this league.
"You have to stabilise first and that is what we are trying to do. It will be a massive season for us if we can stay in this league.
"The club could really kick on next season and go from strength to strength."
Birmingham v Wolves Win to Nil: Wolves 6/1