QPR manager Ian Holloway was "shell-shocked" after the dramatic conclusion to the game in which three goals were scored in the last five minutes.
QPR led 2-1, but the Tykes netted twice before Paul Furlong scored his second goal of the game to salvage a point for the visitors, keeping them in second place in Division Two, four points clear of Bristol City.
Holloway said: "I'm almost speechless. Obviously I've mixed emotions. I'm relieved we got something at the end but disappointed that we'd got ourselves into a great position but didn't make the most of the opportunities we created when we were on top.
"We looked wobbly in defence to start with but got to grips with the game and showed great character at the end to come back and level it. It was an unbelievable end to a very exciting game.
"I knew it would be tough and I felt shell-shocked to see those goals go in at the end."