Rangers thought they would be marking their trophy presentation with a win thanks to a Kris Boyd goal and a double from Kyle Lafferty.
But Well hit back through Jamie Murphy before last minute goals from Steve Jennings and Lucas Jutkiewicz earned a last-gasp draw.
But Hibs' win means they now need Dundee United to win the Scottish Cup to earn European football next term.
Rangers made four changes to their side as Neil Alexander replaced the injured Allan McGregor in goal while Kris Boyd, Sasa Papac and Kirk Broadfoot were also added to the side.
Motherwell made two changes after their thrilling 6-6 draw with Hibernian.
Steve Jennings and Micheal McGlinchey started with Jamie Murphy on the bench and Mark Reynolds out through illness.
Rangers started the game brightly and carved out an early chance when Steven Whittaker tried his luck from distance but he was denied his 12th goal of the season when the effort dipped just over the crossbar.
The home crowd did not have too long to wait to celebrate when the Scottish champions' hard work paid off and they surged into the lead after 17 minutes.
Steven Davis was the supplier with a ball into the box and Boyd did well to hold off Stephen Craigan before turning and slotting past the helpless John Ruddy.
Rangers could have added to their lead seconds later, with Davis again the architect. This time he attempted to set up Kenny Miller but the striker mis-kicked in front of goal and the chance was lost.
Motherwell could have been back on level terms when Jim O'Brien sent a cross in from the right for Lukas Jutkiewicz but he nodded narrowly over the crossbar.
Rangers almost doubled their advantage when Davis pounced on a drop ball and released Boyd on a surging run into the box but he was denied his second goal of the game when a well-timed tackle from Craigan prevented him from unleashing the shot.
Instead it was Kyle Lafferty who found the back of the net four minutes from half-time when he collected a cross from the right from Steven Naismith and stabbed a left-footed shot past the Motherwell goalkeeper.
Motherwell swapped McGlinchey for Murphy at half time and it proved an inspired substitution.
O'Brien made a penetrating run before finding Murphy to rifle home from 20 yards and pull a goal back for the visitors six minutes after the restart.
Rangers then made a change of their own when Miller was replaced by Nacho Novo.
Jutkiewicz then spurned a great chance to level when he found himself with only the goalkeeper to beat but Alexander raced off his line to block.
Hopes of a Motherwell comeback appeared to be dashed when Lafferty grabbed his second of the day after 70 minutes.
Novo embarked on an impressive run before what could have been a shot from the Spaniard just missed Boyd with Lafferty waiting to lash home at the back post.
Well found the back of the net again in the final minute when a rare mistake from David Weir allowed Jennings to bundle home.
Murphy was then fouled by Alexander in the box and Jutkiewicz stepped up to convert from the spot to earn a draw in injury time.
But Hibs' win at Dundee United meant Motherwell were forced into fifth spot in the SPL and missed out on a guaranteed Europa League berth.