But when young striker Antonio German appeared to get a tug in the area from Russell Anderson two minutes from time, Warnock was left fuming.
"It was a blatant penalty," he said.
"I don't need a TV crew to tell me his shirt was being pulled.
" I asked the referee and he told me he didn't see it, but he saw everything else all night.
"He's a young lad and do you have to tell him to cheat and go down, is that the only way to get a penalty?
"It knocked him off his stride. He's frustrated because he knows he would have scored."
Both these teams will not be sorry to see the back of disappointing seasons but they are making heavy weather of dragging themselves clear of the bottom three - Derby are now six points clear of the drop zone and Rangers a point better off.
Forgotten man Lee Cook, who has been beset by injuries for the best part of three years, fired Rangers ahead with the last kick of the first half.
Adel Taarabt, who had Robbie Savage shadowing him all game, for once escaped the Welshman's clutches and played in the unmarked Cook to lash home his first goal since Boxing Day 2008.
But Derby hit back when centre-half Shaun Barker finished like a striker through a crowd of players in the 67th minute.
"Shaun was outstanding at both ends, he headed everything and scored what was, for a non-ball playing centre-half, a very good goal and got an important point for us," said Rams boss Nigel Clough.
"I was unhappy with the manner of the goal we conceded in the 47th minute - if we had made it to half-time then we might have gone on to win it 1-0.
"I would have taken a point beforehand but I'm disappointed with the manner of the goal we conceded."
Derby are without a win in five matches but have drawn their last three as they edge towards Clough's survival target of 52 points.
They held out despite some fierce late pressure from Rangers, with Rowan Vine crashing a shot against the bar five minutes from time.
"We're unbeaten in three is how I'll look at it," added Clough. "And another seven draws will be enough!"