Consequently, Lee Clark's men preserved their Championship status on goal difference at the expense of Doncaster Rovers, but the Scot says that his teammates must now use their experience to enjoy a better season next term.
"We have to use that as motivation never to be in that position again but it is moments like that that football is all about," the 26-year-old told BBC Sport.
"When we were 2-0 down the first thing we heard was our fans singing and that gave us the lift.
"I was celebrating Nikola Zigic's header thinking it was in but I was in the right place to get the decisive touch. I think it is the first headed goal I have ever scored."
City were 2-0 down with 14 minutes remaining at the Reebok Stadium, only for Nikola Zigic to reduce the arrears before Caddis completed the comeback in the dying stages.