It was results elsewhere that meant Derby would stay up irrespective of what happened and QPR nearly snatched this game in the dying seconds with Paul Furlong wasting a golden opportunity from inside the six-yard box.
Rangers took the lead in the 59th minute as Lee Cook crossed from the left and found Marc Nygaard who headed home from close range.
That goal was followed soon after by Derby making a triple substitution as they tried to chase the game.
They squared things up eight minutes later as Tommy Smith embarked on an amazing run from the right to score with an effort that curled past Rangers keeper Paul Jones and into the far corner.
Shortly before the 90 minutes were up, Derby's Darren Moore was sent off for a second bookable offence although Westley later said he could not work out why Moore picked up his first yellow card.
Prior to Nygaard's opener the match had been an uninspiring affair with the best moments in the first half coming when Rams keeper Lee Camp produced a fine save following a Cook effort from 20 yards.
The highlight of the opening 45 minutes came when Gareth Ainsworth came desperately close to producing what would surely have been one of the goals of QPR's season as he hit a volley from at least 35 yards out that caught keeper Camp well off his line and was just inches wide of the post.
Both managers now have the remaining matches to prove they are good enough to keep their jobs for next season.