Liverpool suffer a reality bite facing life after Luis Suarez
It was only April that Phillipe Coutinho scored a late winner against Manchester City at Anfield and Liverpool started to believe for the first time that season they might be serious contenders for the title. What has changed since then?
In a nutshell, Liverpool have sold their best player while City have signed many of theirs to long-term contracts.
When a player of the quality of Sergio Aguero can be dispatched as a substitute, ostensibly the third-choice striker on the night, then beating the City of 2014 can be a daunting prospect.
Yet there is no getting away from it, Luis Suarez was Liverpool's entree into this world of the very elite clubs capable of competing for Premier League and, perhaps, Champions League titles, and without him they are less able of defeating teams like City.
A line can be drawn through the football hierarchy, towards the very top, and its great clubs can be divided into two groups: those who sell their best players and those who buy the best players. City no longer have to sell their best players; they are in the business of buying other teams' best.
There is no shame in being one of the sellers, a group even Manchester United have belonged to since losing Cristiano Ronaldo to Real Madrid. Over the course of the season it may well be that Brendan Rodgers' reinvestment of the Suarez profit margin will prove to be astute.
Perhaps Mario Balotelli, in the directors' box at the Etihad last night, will finally deliver on his undoubted promise. But you would be hard pressed to imagine him replicating Suarez's returns.
That was the prevailing mood as one watched City pick off Rodgers' team, first with Stevan Jovetic's brilliantly opportunist first half goal and then with another beautifully worked after half-time before Aguero added the third.
The City fans knew it too, singing Suarez's name as their team went three goals ahead as a reminder that these are the sort of players who arrive once in a generation and, once gone, are almost impossible to replace.
That is not to say that the Liverpool team Suarez has left behind is a lost cause. They still look good for the top four. At times Rodgers' side were excellent; they had the best of the first half and Rickie Lambert, as a substitute, led an admirable late surge that led to their goal. Yet to beat City these days, it has to be close to perfect.
They are a squad of daunting depth, with a work ethic that allows them to break down teams over time. Jovetic, with another two goals, is emerging as a fine Premier League-ready player.
Having been on the back foot for much of the first half, they gradually shut down the biggest threats that Liverpool posed them, through Daniel Sturridge and Raheem Sterling, and went about the business of winning the game.
It takes just a moment at this level for a mistake to be made, an advantage to be gained and a goal to be scored.
So it was four minutes before half-time when Alberto Moreno's pink boot failed to connect with the loose ball in his own box and a minor catastrophe unfolded before him. A heartbeat earlier, Jovetic had steered it away and then, with his next touch, hit a shot so hard it went through Simon Mignolet's legs.
For Moreno, it was an introduction to life at the top of the Premier League where, for defenders in particular, reputations are made and lost in moments like that. This had been a first half between two beautifully balanced teams with no margin for error at either end.
Until then Liverpool had the best of it, closing City down relentlessly in midfield. Coutinho wriggled clear of Yaya Toure on 29 minutes and the big City midfielder earned himself a booking as he reached down to try to drag the Brazilian back.
Sturridge's turn and shot in the City area four minutes later was the best individual moment for his side.
On that occasion Vincent Kompany flung his arms wide to indicate he was beaten and would not be doing anything daft to try to reel Sturridge in. It was that kind of penalty box sharpness that England lacked so badly in Brazil this summer at the end of a long, tiring season. But Sturridge hit his shot straight at Joe Hart and City got away with it.
If there was a regret for Rodgers in his team's attacking play it was that Sterling, one of five Englishmen in the starting XI for Liverpool, did not find himself on the ball enough.
His staggering pace threatened to expose Pablo Zabaleta on one occasion, but City managed to prevent the winger from isolating their defenders more often than not. As ever, Liverpool are not wedded to the slow build-up and will look to Steven Gerrard for the quick ball over the top.
But City are a resolute bunch and it was Samir Nasri's excellent chip into David Silva from the right that began the sequence that led to the goal. Dejan Lovren's clearing header did not do the complete job, Moreno failed to react quickly enough and Jovetic did the rest.
There was a marvellous burst from Sterling past Fernando early in the second half which drew a foul from the Brazilian but on 55 minutes Jovetic pounced again.
This time it was a flick from Silva's ball into the path of Nasri on the right who crossed to the back of the box, where Jovetic's run took him into the right position to stroke the ball in with his left foot.
Aguero came on for the injured Edin Dzeko on 68 minutes and a moment later angled his run across Lovren, beat the defender for sheer pace and tucked the ball past Mignolet.
That was the game, although there was time for Lambert to force a goal for Liverpool when he met Sturridge's outside-of-the-foot cross at the back post.
Hart did well to save but could do nothing to keep out the rebound off Zabaleta.
This season there will be few who get as close to City as Liverpool managed, but that will be scant consolation when they remember that victory in April and the reality of life post-Suarez.