With 70 minutes of this match gone Manchester City seemed to be providing a thrummingly well-engineered glimpse into the medium-term future, not so much outclassing Tottenham as simply refusing to let them play at all, and delivering an invigorating pointer towards what the Premier League – and even Europe – might expect next season. And yet, by the end of the match Steffen Freund, prominent throughout in his capering managerial wingman role, could be seen pinching the cheeks of a junior Tottenham ballboy with such celebratory vigour that the ballboy was still rubbing them in discomfort as he walked down the tunnel a few minutes later. Behind him City's players, trudging off the White Hart Lane turf in watery spring sunshine, looked as through they could have done with a pinch or two of their own after one of the season's more improbable 3-1 defeats.

And yet there was something oddly familiar too here, a temptation to see in City's glossily expert capitulation a cartoonish sense of a season in microcosm. City have made a habit of veering on to the hard shoulder and offering Manchester United the road in the title race. Here they again looked like the best team in the country for most of the match but still managed to end it as glum-faced champions un-elect, offering United the chance to take back an expensively acquired league championship at the earliest opportunity with victory on Monday night at home to Aston Villa.

"They [United] are not better than us, but they deserve to win the title," Roberto Mancini said afterwards. Which begs the obvious question: how did that happen then? And where does it leave the manger who has overseen such underperformance?

In a sense City's annihilating first-half show – a 1-0 thrashing of comprehensive proportions – makes defeat seem even more dysfunctional. City were better in every department. In the battle of the side-winding English ball-shuttlers, Scott Parker was overshadowed by Gareth Barry. He may have attracted the rather unkind nickname "Davros" from some Spurs supporters – tribute to his favourite slow-motion, 180-degree turn in possession, reminiscent of the chair-bound swivels of the Dalek overlord – but Parker battled gamely as ever. He was simply outgunned by City's superior central power; just as City's attack had both teeth and high-class lateral movement, whereas Spurs had Emmanuel Adebayor. If there is some consolation in the fact that Spurs have won merely once in the Premier League when Adebayor has scored this season, it is perhaps to be found in the fact that at least he doesn't score very often. With Carlos Tevez in full rampant scullery-mouse mode, the contrast between the Togolese and the world's least sedentary itinerant footballing hired gun could not have been more pronounced, not least in Tevez's scamper and lovely pass inside for the opening goal, which was beautifully finished by Samir Nasri.

Of course, Tottenham won this game as much as City lost it and there will be much credit given to André Villas-Boas, whose substitutions and change of shape, allowing Gareth Bale licence in the second half to rove from his central position, led directly to Spurs' three goals in seven minutes. Great players make tactical tweaks into masterstrokes (Villas-Boas also looked to have picked the wrong team for 70 minutes) and Bale's dinked finish for the crowning third goal, delivered at full speed, 82 minutes into the match, but still as dainty as a man skimming the top off his boiled egg, will linger in the memory. Similarly, Villas-Boas deserves credit for bringing on the more physically imposing Tom Huddlestone for a battered-looking Parker, who spent his hour on the pitch buzzing around Yaya Touré like a wing-weary bumblebee trying to bring down an articulated lorry.

But what exactly were City doing all that time? In a way, this has been the story of their season, betrayed by a sense of drift at vital moments. Blessed with endless attacking angles and intelligently led on the right by James Milner in the first half, City essentially vanished in those final 15 minutes, unable to find the secondary surge that was so in evidence towards the end of last season. Some will point to Vincent Kompany being at fault for Tottenham's first two goals. But City's real failing here was an inability to do enough with their patent superiority. Despite playing like champions – driving forward like champions, tackling in midfield like champions – they still managed to leave the pitch with Spurs fans singing "you're not champions any more".

Mancini has looked increasingly secure as the title has slipped away amid the consolations of familiarly steamrollering form in league and cup. But here his assistants were particularly upset at the final whistle, with David Platt involved in a wretched moment of shoulder-barging bravado with José Mário Rocha, Spurs' fitness coach. No doubt a coherent medium-term plan is in place at the Etihad Stadium. But this was a strangely decelerating display, and untimely too for a champion team who have displaced their decisive champion's bite a little too often for comfort this season.