Kris Commons fired the home side into the lead inside 15 seconds - but instead of a Hoops romp, Scott Vernon levelled with a minute of the first-half remaining and Josh Magennis grabbed a double to set the Dons on the way to what would have been an unlikely victory.
However, Celtic showed the spirit of champions and Charlie Mulgrew reduced the deficit before Gary Hooper equalised with three minutes remaining leaving the stage set for Samaras, who had replaced Beram Kayal, to hook in the winner with seconds left.
It was a remarkable afternoon's football but when the dust had settled the Hoops had strengthened their grip on the SPL title.
Mikael Lustig, Emilio Izaguirre and Commons returned to the starting line-up for Celtic with Rami Gershon, Miku and Dylan McGeouch dropping out, only the latter starting on the bench.
Dons manager Craig Brown, 72, who revealed during the week he would be standing down at the end of the season although taking a seat on the board as a non-executive director, made one change with Magennis in for the injured Clark Robertson who was out altogether.
Fans were still taking their seats when Commons opened the scoring.
Gary Hooper's head-flick was controlled by Anthony Stokes who turned and rolled the ball into the path of the midfielder and he drilled it low past Jamie Langfield and into the corner of the net.
In the eighth minute Langfield did well to tip a Charlie Mulgrew free-kick from 25 yards over, before - at the other end- Magennis went down in the box under a challenge from Efe Ambrose and Wilson but referee Steven McLean ignored penalty appeals.
In the 33rd minute Commons floated a shot from the left-hand side of the box wide - and eight minutes later Langfield blocked from Stokes.
Moments later, the Irishman just missed the target with a right-footed drive from the edge of the box and the Hoops were soon made to pay for their lethargy.
The warning came when Vernon headed a Ryan Jack cross wide of the far post from six yards out but a minute later he was presented with an even better chance and this time he took full advantage.
The powerful Magennis robbed Wilson inside the Celtic box and with the Hoops defender looking for a foul, the Dons striker calmly rolled the ball back for Vernon to fire into the net from 12 yards.
The Celtic fans did not appear too concerned as the interval whistle sounded but they could not contain their anger when the visitors took the lead eight minutes after the break.
In a swift Dons move former Rangers midfielder Gavin Rae took a Vernon pass and set up Magennis, who had time and space to fire the ball past Forster.
Celtic immediately upped the tempo and Stokes had a header from an Izaguirre cross saved by Langfield.
There was more woe for Celtic on the hour when a Johnny Hayes corner was cleared only to Rae - and he drove it back in on goal with Magennis getting a touch before it ended up behind Forster.
Lassad Nouiou came on for Stokes but it was Mulgrew who got Celtic back in the game in the 68th minute, following a Commons corner, when his deflected shot from inside the box spun past the helpless Langfield.
The Celtic support was lifted and urged their side forward.
Langfield punched away a ferocious Mulgrew free-kick before the Dons defence cleared and then he parried a powerful Hooper drive.
Three minutes from time Hooper drew Celtic level when he pounced after Ambrose's header from a Commons corner had been cleared off the line by Dons substitute Peter Pawlett, who had come on for Hayes.
Celtic pushed for the winner and in the last seconds of four minutes off added time, Samaras obliged from close range after Lassad had headed back a Commons free-kick.
There was barely time for the home fans to celebrate before the final whistle sounded.
Meanwhile, Billy McKay's controversial penalty secured Inverness a 2-1 home win against Highland rivals Ross County, lifting them above the Staggies into third place.
The Northern Ireland striker's 24th goal of the campaign ended County's 11-game unbeaten run and has all but ensured Inverness will have their first ever top-six SPL finish.
McKay netted the winner in the 59th minute after referee Iain Brines pointed to the spot when Charlie Taylor went down, but there were strong suggestions the full-back was making a meal of it.
It came after Andrew Shinnie's close-range opener in five minutes for Caley Thistle was cancelled out by a magnificent 30-yard strike from County's Paul Lawson.