An Alfredo Morelos handball allowed Lewis Ferguson to earn Aberdeen a point against 10-man Rangers.
Rangers had Ryan Kent sent off as they dropped cinch Premiership points for the first time under Giovanni van Bronckhorst to leave them four ahead of Celtic.
The visitors took the lead against the run of play in controversial circumstances in the 20th minute at Pittodrie.
Ianis Hagi netted from close range seconds after the Dons had a strong penalty appeal waved away by Kevin Clancy when Allan McGregor caught Ryan Hedges.
Clancy did point to the spot in the 73rd minute after Morelos handled and Ferguson converted.
Kent was harshly sent off in the 83rd minute following a challenge on Scott Brown but Rangers held out for a point.
Rangers had American midfielder James Sands making his debut while Scott Wright started against his former club.
The hosts had the better of the opening exchanges. Teddy Jenks hit the outside of a post from 22 yards after a Joe Lewis clearance initially put Rangers on the back foot, and the on-loan Brighton midfielder soon forced McGregor to stop at full stretch from similar range.
Brown was heavily involved from early on, losing the ball before Kent shot straight at Lewis and then blazing over at the other end from 25 yards following Funso Ojo's cutback. The former Celtic skipper was pushed to the ground by Morelos but Clancy opted to have a word with both.
The major first-half talking point came after Jonny Hayes sent Hedges clear with a long diagonal ball. The Dons player got a foot to the ball as McGregor threw himself at it and bumped into the Welshman. There was clear contact with Hedges' leg and the Aberdeen player went down but Clancy was unconvinced and Rangers played on.
The visitors quickly worked the ball forward and Wright found Kent with a crossfield ball. The winger whipped a cross in between Ross McCrorie and Lewis, and Hagi supplied a deft touch to knock it past the static goalkeeper from four yards.
Ferguson almost caught McGregor out from the restart but his effort landed on the roof of the net and Rangers got more control of the game for the remainder of the half.
Brown, who was booked for a challenge on Kent, had a couple of chances following set-pieces early in the second half. He volleyed well over from 12 yards before heading over from a more difficult opportunity.
The Dons were struggling to create chances from open play but they got their spot-kick following a corner when Morelos moved his arm towards the ball after Ferguson headed towards goal.
Clancy had little doubt this time and Ferguson sent McGregor the wrong way despite a gust of wind blowing the ball back towards him as he embarked on his run-up.
Morelos was booked for the handball but he almost redeemed himself with a tremendous volley which Lewis dived to push over.
Kent was booked for a foul on Hayes shortly before catching Brown just after the Dons skipper played the ball. There was not much in it but Clancy flashed a second yellow card.
The Dons nearly won it with the final kick but Jenks fired over.
