Manchester City were shown that a lot of work remains to be done if they have to overcome last season's woes as they suffered a 2-0 home defeat to Tottenham on Saturday.
Brennan Johnson and Joao Palhinha struck for the Europa League winners just before half-time as Spurs went top of the table, making it a perfect start for Thomas Frank after two league games in charge.
City's run of four consecutive titles came to an end last season as they finished a distant third behind Liverpool and Arsenal.
A 4-0 thrashing of Wolves on the opening weekend of the season showed glimpses of a new-look City back to their best.
However, a series of defensive issues remain unresolved. Also, manager Pep Guardiola must decide who will be his number one goalkeeper going forward after a day to forget for James Trafford.
Much of the post-match analysis was around goalkeeper Trafford, who returned to the Etihad Stadium this summer in a £27 million move from Burnley.
Johnson's opener was hard to prevent but he could have been sent off for a clumsy challenge on Mohammed Kudus before his huge error allowed Palhinha to score in first half stoppage time.
Ederson, back from illness, watched from the bench as speculation about his future and City's potential move for Paris Saint-Germain star Gianluigi Donnarumma rumbles on.
Saturday's match started with chances at both ends. Pedro Porro fizzed an effort into the side-netting after seeing a free-kick blocked before he gifted Omar Marmoush a chance.
Home debutant Rayan Ait-Nouri had to be replaced by Nathan Ake midway through the first half as both sides battled for a breakthrough, which Erling Haaland's vision nearly brought in the 28th minute.
The City striker followed an impressive drive inside with a smart ball through for Marmoush to get away a first-time shot that Vicario spread himself to stop.
Seven minutes later Spurs found the net. Pape Matar Sarr's flicked header put through Richarlison, who burst free and sent across a low ball for Johnson to slam home.
Initially ruled out for offside against the Brazil international, the goal was eventually awarded and the VAR's review sparked wild celebrations in the away end.
City spiralled from that point. Tijjani Reijnders caught Porro just outside the box after Trafford avoided red despite appearing to handle outside the box and clattering Kudus as he cleared.
But the goalkeeper would end the half disheartened after collecting a short goal kick and passing short in his own box to Nico Gonzalez, who had Sarr on his back.
The ball went loose to Richarlison and Trafford could only push it on for Palhinha to drive home Spurs' second in stoppage time.
Micky van de Ven was fortunate to avoid a penalty for catching Oscar Bobb before Frank's men eventually settled, with Richarlison sending two almost identical looping headers over.
City upped the ante in the final 20 minutes, with Van de Ven throwing himself in front of an attempt by substitute Phil Foden.
Bernardo Silva headed onto the roof of the net and play became stretched as Spurs frustrated City.
Trafford denied substitutes Dominic Solanke and Wilson Odobert in stoppage time but the damage was already done.
