Town went to the runaway leaders on the back of successive defeats but became the first Championship side to deny Cardiff a goal as the game finished 0-0.
The visitors might even have nicked it at the end as Frank Nouble missed a chance, but McCarthy said: "It was probably a fair result overall. I would have taken it before and I'm happy with it now.
"We always work hard every week. We get our stats and we work as hard if not harder than everyone else and they really have bought into that team shape. They've bought into everything I've tried to do.
"I tried to make us organised and hard to beat and if you work as hard if not harder than everyone else than you'll have a chance."
Ipswich are now six points clear of the bottom three, but the manager said: "I'm still looking behind me. Whatever we've done so far it can change so quickly. We'd lost two on the bounce and I didn't want to lose three league games on the bounce."