Key points
Rampant Hearts powered eight points clear of Celtic at the top of the Scottish Premiership to strengthen their early-season title credentials and deepen the malaise around Brendan Rodgers' side.
Alexandros Kyziridis' fine strike and Lawrence Shankland's penalty gave the Hearts team a two-goal advantage that the title holders could not recover from.
The young defender - one of three youngsters in the Celtic starting lineup - slashed into his own net early on to put Hearts ahead at a bouncing their home ground, and it was the youngster's infringement that led to the penalty.
Callum McGregor's classy first goal of the season had quickly cancelled out Hearts' opener, and Benjamin Nygren almost put Rodgers' team in front, choosing placement over power and allowing Alexander Schwolow to make a crucial stop.
But Derek McInnes' irrepressible Hearts regained dominance to consign Celtic to back-to-back losses for the initial occasion since last year.
It also gives the Edinburgh side a commanding advantage at the top of the table.
The last time they were this far ahead was in 2005-06 under their former manager, when they ultimately finished second - one of just four occasions that a team has not secured the title having held such a lead in the past 27 years.
McInnes, whose former team were second to Celtic on four occasions, has been at pains to play down title talk, as the club seek their maiden league title since the 1960s.
The Celtic boss has seen it all before at the club - both flawless and stuttering starts to a season. He's yet to finish second best.
But on Sunday's evidence, this Hearts team showed they need to be taken seriously.
Hearts started with the confidence of a side unbeaten in the league this season - fans' favourite Kyziridis poked a cross in for Shankland to stab wide.
Celtic didn't aid their cause with some uncharacteristic carelessness in possession and they buckled under their initial test.
Claudio Braga's header was tipped onto the woodwork by the Celtic keeper and the follow-up from Shankland was diverted goalwards by the unfortunate Murray, in for the injured Cameron Carter-Vickers.
The away side grew into the contest and started building moves. From one such move, Sebastian Tounekti released Tierney to square for the captain, who rolled in.
Aside from the opportunity for Nygren, the visitors found it hard to generate chances for lone frontman Jonny Kenny or his substitute Yamada amid the unavailability of stricken attackers their key strikers.
The home team rediscovered their energy and adaptability in attacking from across the final third. Kyziridis, one of the finds of the club's relationship with shareholder Tony Bloom's Jamestown Analytics, struck low past Schmeichel from the edge of the box.
Immediately after, the defender tripped the midfielder in the inside right channel and Shankland scored. And it could've been an even more handsome win, had substitute Ageu not been stopped by Schmeichel.
Celtic's second half was partially encapsulated in two incidents involving big-money recruit Engles.
The midfielder's wayward free-kick delivery was in sharp opposition to his midweek exploits in the Europa League win over their Austrian opponents and the national team player was then booked for a cynical foul.
Hearts head coach Derek McInnes: "You see how hard the players work, the togetherness. That's not sufficient on its own to win games consistently.
"What we have got, is good technical ability. You're witnessing it from multiple individuals who have been here before. Some of the new signings are keen to demonstrate their quality.
"We've got a good thing going at the minute, but it's only three points. It's important for us to maintain this form. We've got much work ahead, plenty to improve. After the first two rounds is normally an indication of your standing."
The Celtic boss: "The second goal was disappointing from our perspective. We failed to push up when the ball went back as a line so when they play it, they should have players offside but didn't. We have got to do better with the attempt.
"Plenty of matches to play for. It's still so early. It's just nine matches. Obviously, being eight points behind is not what we would want. The positive is there's so many games to play.
"We now have to focus on the here and now and look to achieve greater stability and more quality in our play."
Celtic are back at home on Wednesday against promoted side Falkirk (19:45 GMT). At the identical hour in the Scottish Premiership, Hearts are at their opponents' ground.
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