Scott Severin’s drive in 68 minutes was not going to cause Ronald Waterreus a problem but it diverted off the Frenchman to wrong-foot the Dutchman and the ball flew into the Rangers net.
It now means that the Light Blues trail Hearts by five points with just four matches remaining and now must rely on the Tynecastle men losing twice while winning all of their own games. It seems unlikely.
Rangers certainly dominated the first half in terms of possession and attacking play but their inability to turn this control into something tangible was a source of frustration to the fans.
Indeed, although penned in their own area for most of the first half Aberdeen might have scored twice through two very decent chances.
Rangers were over-elaborate in their build-up and although under siege the Dons defended solidly.
Skipper Barry Ferguson showed some urgency and precision in the 17th minute when he cleverly laid the ball into the path of Kris Boyd to give the striker a shooting chance on his left side.
It was a tight angle and Boyd hit the shot well enough but he could not angle it away from Jamie Langfield who held it fairly comfortably.
Four minutes before this Ronald Waterreus was nearly caught out by a Zander Diamond header from Jamie Smith’s corner which seemed to strike the Dutch keeper on the thigh as he dived the opposite way.
Then in 20 minutes Alan Hutton allowed Diamond’s cross to reach Gary Dempsey inside the Rangers box and the Aberdeen midfielder only just missed the target with a right foot volley.
It was a warning to Rangers that they needed to increase their tempo. They managed this towards the end of the first half but it still did not produce a goal.
Boyd was unlucky with a header from Chris Burke’s corner in 24 minutes when it beat Langfield but was deflected wide by Smith who was positioned on the left post.
Brahim Hemdani blasted one over the bar in 31 minutes and then Langfield punched a Kyrgiakos header over the bar in 38 minutes.
Diamond almost headed into his own net from the resulting corner but Aberdeen survived again and the frustration continued for Rangers.
That frustration almost turned to dejection two minutes into the second half when only the woodwork prevented Rangers from going behind.
Hutton gave the ball away to Smith who quickly played in Steve Lovell down the left. The striker then cut the ball back to Dempsey who smacked a right foot shot off the crossbar.
It was a let-off and Rangers capitalised in the best possible way by grabbing the goal they craved and it was Boyd who got it.
Kyrgiakos hooked a high ball into the box, Prso knocked it down for Boyd who moved cleverly onto his left side before hammering a left foot shot which Langfield could not prevent from going into the net.
The relief around Ibrox was tangible but instead of going on to kill off the match, Rangers seemed content with their lead. It was to prove so costly.
Aberdeen won a free kick on the left side of the Rangers box in 68 minutes when Kyrgiakos slammed into Dempsey to earn a yellow card.
Smith played the dead ball short to Scott Severin who drove a right foot shot which deflected off the heel of Julien Rodriguez, wrong-footed Waterreus and flew into the left corner of the Rangers net.
McLeish threw on Murray, Novo and then Gavin Rae in an attempt to rescue the situation but it was all in vain.
Rangers were five points behind Celtic with four games to go last season and won the championship. Who was it said Keep Believing?