Gary Hooper's 39th-minute header - the striker scoring in four successive league games for the first time since February 2008 - looked like handing Wednesday a rare victory in the Welsh capital.
But Sol Bamba secured a 1-1 draw in the fourth minute of time added on when Keiren Westwood pushed out Lee Tomlin's free-kick and Nathaniel Mendez-Laing drove the rebound across goal.
"Both Sheffield Wednesday and ourselves are two of the better sides in the league," Warnock said. "They have the purists and we have the never-say-die attitude and some good players as well.
"It's like winning a game, I've been on the other end of games like that and you're distraught that you can't believe you've thrown points away.
"But I thought we deserved it in the second half, we had 12 efforts to their two."
Cardiff lost the leadership of the Sky Bet Championship in midweek when they suffered a first defeat of the season at Preston. And Warnock felt there was a hangover from that 3-0 reverse as Wednesday passed their way around Cardiff in the first half.
"We carried on where we left off at Preston as we were on the back foot," Warnock said. "I was delighted to get to half-time at 1-0 because I thought we were vulnerable then.
"We were feeling sorry for ourselves and I told them we needed to get back on the front foot and gamble a bit more. Sol Bamba was 10 out of 10 today, he was a colossus and dragged us through."