A Berlin-based political analyst with a decade of experience covering European affairs and a passion for investigative journalism.
Key points
The dominant Edinburgh side powered eight points clear of their Glasgow rivals at the summit of the Scottish Premiership to strengthen their early championship claims and deepen the malaise around Brendan Rodgers' side.
A superb goal from Kyziridis and a spot-kick from Shankland gave the Hearts team a two-goal advantage that the title holders could not overcome.
The young defender - among three youth players in the Celtic XI - scored an own goal early on to put the home side ahead at a energetic their home ground, and it was the youngster's infringement that led to the spot-kick.
A stylish finish from McGregor of the season had swiftly equalized Hearts' opener, and the Swedish attacker almost put Celtic in front, opting for finesse over power and allowing the Hearts keeper to save from close range.
But the unstoppable Hearts side regained dominance to hand the visitors to back-to-back losses for the first time since 2023.
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 George Burley, when they ultimately finished second - a rare instance that a team has not secured the title after building such an advantage in the past 27 years.
McInnes, whose Aberdeen side were second to Celtic on multiple times, has been at pains to downplay title talk, as Hearts seek their first top-flight crown since 1960.
Rodgers has experienced this previously at the club - both perfect and shaky beginnings to a season. He's yet to finish second best.
But on the weekend's performance, this Edinburgh outfit showed they deserve serious consideration.
Hearts started with the self-assurance of a side unbeaten in the league this season - the popular attacker delivered a ball for the striker to fire off target.
The Glasgow team didn't help themselves with some unusual sloppiness in possession and they buckled under their first real examination.
Claudio Braga's header was touched on to a post by Kasper Schmeichel and Shankland's return ball was turned into the net by the unfortunate Murray, in for the injured Cameron Carter-Vickers.
The away side grew into the contest and started building moves. From a flowing attack, the midfielder released the full-back to square for the captain, who rolled in.
Apart from the opportunity for Nygren, Celtic struggled to create much for lone frontman Jonny Kenny or his replacement Shin Yamada amid the unavailability of injured forwards Kelechi Iheanacho and Daizen Maeda.
Hearts rediscovered their energy and adaptability in attacking from across the final third. Kyziridis, a standout performer of the club's relationship with shareholder Tony Bloom's Jamestown Analytics, fired a low shot past the goalkeeper from the just outside the area.
Almost straight away, the defender fouled the midfielder in the inside right channel and Shankland converted. And it could've been an even more handsome win, had substitute Ageu not been denied by the shot-stopper.
Celtic's second half was partially encapsulated in a couple of moments involving record signing Arne Engles.
The set-piece from Engles delivery was in stark contrast to his midweek exploits in the continental victory over Sturm Graz and the national team player was then booked for a cynical foul.
Hearts head coach Derek McInnes: "The effort from the squad is evident, the team spirit. That's not always enough to win games week in, week out.
"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 eager to show that.
"We're in a positive moment at the minute, but it's just one win. It's crucial for us to maintain this form. We've got much work ahead, loads to do. After the first two rounds is normally an indication of where you are."
Celtic manager Brendan Rodgers: "The second goal was disappointing from our perspective. We didn't move when the play was recycled as a defensive unit so when they pass the ball, they ought to be caught offside but weren't. We have got to improve with the shot.
"There's still so many points to play for. It's still so early. It's only nine games in. Clearly, being eight points behind is not what we would want. The comfort is there's so many games to play.
"Our attention must turn on the present and look to find more consistency and more quality in our play."
Celtic are returning to their stadium on Wednesday against promoted side Falkirk (19:45 GMT). At the same time in the top division, Hearts are at their opponents' ground.
A Berlin-based political analyst with a decade of experience covering European affairs and a passion for investigative journalism.