playmaker slotted another penalty.
As their opposition continued to score their points in threes, the Reds were staying aggressive and after a slashing Peter Hynes break, Cooper was able to position himself for a simple field goal.
With 20 minutes remaining New South Wales again slashed the deficit to six points when Barnes kicked his fifth for the night, keeping the Waratahs within sight.
With Barnes on the bench, it was left to replacement Daniel Halangahu to kick the next penalty after Van Humphries was ruled to have taken out a kick chaser.
With 10 minutes left in the game Queensland's electric scrum-half Will Genia burst down the blind side, chipped the last defender and ran through to be awarded a penalty try after 'Tahs defender Ben Mowen was ruled to have impeded his chase.
Cooper converted the try from right in front, but the Reds' 10-point lead lasted only minutes before a left-hand side overlap resulted in an unconverted try to the Waratahs, and a 23-28 score line.
The Waratahs were reduced to 14 men when referee Craig Joubert yellow-carded Mumm for a cheap shot on Reds hooker Ezra Taylor.
With less than two minutes left on the clock and the Reds on the verge of snapping a five-game losing streak against the Waratahs, Wycliff Palu crashed over to hand his side the win and break the hearts of the Queensland fans.
With the scores level, the teams again had to be separated before Halangahu could kick the Waratahs to victory from right in front.