Kenny McLean looked to have given an ideal parting gift to the home fans in his final appearance for the Dons at Pittodrie when the Norwich City-bound midfielder converted a 14th minute penalty to give them the lead.
But Derek McInnes’ team were denied the victory which would have sewn up a fourth consecutive runners-up spot in the top flight when Ross McCrorie levelled for Rangers midway through the second half.
It leaves Aberdeen just a point ahead of third-placed Rangers going into Sunday’s final round of top-six fixtures. If fourth-placed Hibs, now three points behind Rangers, lose tonight’s Edinburgh derby, then both Aberdeen and Rangers will be at least assured of Europa League participation next season.
With a differential in SPFL prize money of £560,000 between second and fourth place in the table, it was not only status and the guarantee of European football which was on the line at Pittodrie.
Not that any additional incentives are needed when these two bitter rivals cross swords. While the quality of the football may have left much to be desired for long spells, there was no shortage of intensity in the approach of both sides on an evening which kept referee Steven McLean fully occupied as he cautioned 10 players - four from Aberdeen and six from Rangers.
Aberdeen’s breakthrough from the contentious penalty he awarded them came very much against the run of play and significantly altered the pattern of the contest in the home team’s favour.
Rangers had opened up by far the sharper and more progressive outfit, moving the ball quickly and purposefully in those initial stages as they hemmed the Dons into their own half.
Alfredo Morelos should have given the visitors a lead in the fifth minute. Latching onto a Graham Dorrans pass inside the penalty area, he failed to get enough purchase on his close range shot which was well saved by Joe Lewis.
Morelos made what referee McLean considered a more telling touch in the other penalty area nine minutes later to concede the penalty which brought Aberdeen’s performance to life. It was certainly a highly debatable decision as the striker appeared to get a toe on the ball when challenging Kenny McLean as Rangers struggled to clear a corner.
Once the protests of the visitors had subsided, McLean stepped up and confidently sent Jak Alnwick the wrong way from the spot.
While Rangers were clearly rattled by the setback, Aberdeen were energised and dominated much of the remainder of the first half. Now playing with confidence and a higher tempo, McInnes’ men pushed hard to increase their lead and Alnwick was called into action when he saved from Ryan Christie after a surging run from the on-loan Celtic playmaker.
McLean then came close to beating Alnwick again, this time with a thunderous shot from all of 30 yards which smacked back off the crossbar with the Rangers ‘keeper flat-footed.
As Rangers struggled to regain their earlier composure, racking up four bookings before the interval in the process, they also had to make a change when Dorrans limped off to be replaced by Sean Goss.
They continued to look vulnerable and Alnwick was almost deceived by a cross-cum-shot from Shay Logan, just managing to clutch it before it crossed the line. There was a let-off for Rangers four minutes before the break when a poor defensive header from Andy Halliday presented McLean with a clear sight of goal but his contact on the shot wasn’t clean enough, allowing Alnwick to make a comfortable save.
The half-time whistle would have come as a relief to Rangers caretaker manager Jimmy Nicholl and the players under his temporary command. Whatever message the veteran coach imparted during the interval, it succeeded in restoring a sense of urgency and direction to their work.
Morelos should have brought them level in the 56th minute when he was picked out by James Tavernier’s cross but could only direct a tame header straight at Lewis from six yards. But Rangers were now the aggressors once more and they merited their equaliser when it did arrive seven minutes later.
It was a frustrating goal to concede from Aberdeen’s perspective as they failed to react quickly enough inside their own penalty area after a shot from Morelos had been blocked by Scott McKenna. As the ball spun into the air, it was McCrorie who was alive to the situation as he leapt highest to head it beyond the left hand of Lewis into the corner of the net.
Both sides had chances to snatch victory in a frantic closing spell, Goss blazing over for Rangers before Aberdeen substitute Greg Stewart did likewise for the hosts.
ABERDEEN: Lewis, Logan, O’Connor, McKenna, Considine; Ball (Stewart 71), Shinnie; Mackay-Steven (Rooney 90), Christie, McLean; Cosgrove (May 79). Subs not used: Woodman, Arnason, Reynolds, Wright.
RANGERS: Alnwick, Tavernier, Martin, Bates, Halliday; McCrorie; Candeias, Dorrans (Goss 32), Holt (Cummings 61), Murphy; Morelos. Subs not used: Kelly, Hodson, Rossiter, Alves, Docherty.