Glenn Loovens' last-gasp goal earned Celtic a 2-1 win over Hearts to send them to the top of the SPL.
Suso Santana gave Hearts a shock lead after just five minutes following a mistake by Celtic goalkeeper Artur Boruc.
Celtic drew level on 56 minutes when Chris Killen headed home Shaun Maloney's cross.
The Bhoys grabbed the winner in the closing seconds when Loovens rose highest to power home Aiden McGeady's cross to send the home fans into raptures.
Hearts boss Csaba Laszlo sprung a surprise by starting central defender Ismael Bouzid up front, supported by David Obua - and it paid early dividends when the Gorgie side took a fifth-minute lead through Suso.
The Jambos' Spanish midfielder took advantage of slack play by Scott Brown in the middle of the park and raced towards the Hoops penalty.
He slammed in a shot from 25 yards which looked saveable but Boruc allowed the ball to slip past his grasping fingers and into the corner of the net.
The goal stunned the Parkhead faithful, who urged their side back in to the game.
The Gorgie side retreated as Celtic piled forward but there was enough hesitancy in the home side's play - and growling from the stands - to give the visitors hope of building on their lead with the occasional breakaway.
In the 26th minute, after Hearts defender Craig Thomson had clattered Fox 30 yards from goal, Maloney crashed the free-kick off the crossbar, leaving the
Edinburgh side scurrying to clear the danger. It was the closest Celtic would come before the break.
Marius Zaliukas hobbled off in the 37th minute to be replaced by Arvydas Novikovas, Bouzid returning to his more natural position to help the visitors rally in the closing stages of the half.
Moments later, from Thomson's corner, Boruc pulled off a good save at his left-hand post from Bouzid's powerful header.
Then, in the 41st minute, Hearts midfielder Andrew Driver raced clear of the Celtic defence to pick up Balogh's clearance - but Boruc parried his angled shot before Gary Caldwell raced back to clear the ball off the line.
The two Hoops players had a brief but furious spat, a sign of the tension and nerves which had gripped Parkhead by the time referee Dougie McDonald had signalled the end of the first 45 minutes.
The home fans made their feelings known at the half-time whistle but Celtic appeared rejuvenated at the start of the second period.
In the 48th minute Maloney challenged Balogh at the near post after Killen had attacked Fox's cross from the left, and the Jambos' defence were relieved to clear the loose ball.
Moments later there was more panic inside the Gorgie box as Balogh scrambled around on his knees in a melee, trying to thwart McDonald and Killen and somehow the ball stayed out the net - but only for a few more minutes.
In the 55th minute, after Killen's 30-yard volley had been punched clear by Balogh, Maloney picked up the loose ball wide on the left.
The Scotland midfielder put it back across goal and the New Zealand international came flying in at the back post to power in a header to level the score.
As Celtic almost inevitably began playing with more confidence, McGeady drove a snapshot from 30 yards crashing off the top of the crossbar and behind.
It was a frantic end to the game. In the 71st minute McDonald hammered in a shot from outside the box which beat Balogh but rebounded off the post. The ball fell kindly to the unmarked Killen who, from 12 yards, almost comically miskicked, allowing McDonald a second chance. Although he rounded the keeper and got a shot in, Thomson cleared off the line.
Hearts first real threat of the second half came in the 81st minute when, on the counter, Obua sent a 30-yard drive whistling past Boruc's left-hand post.
When Celtic had their penalty claim turned down it looked they would have to settle for a point but Loovens popped up with his crucial goal.