If it was a night that carried the now familiar whiff of fireworks for Liverpool, it was one that reeked of total humiliation for Manchester City.

Even after dazzling showings from their goalscorers Kevin De Bruyne, Raheem Sterling and Phil Foden in an irresistible 4-0 win, the gap is 20 points. The analysis of where a Premier League title defence helmed by the most celebrated coach of a generation went so far awry should be unsparing.

But, as Pep Guardiola has pointed out frequently since the Premier League title was ceded to Merseyside, City still have plenty to play for this season. The EFL Cup can still be joined in the trophy cabinet by the FA Cup and the Champions League.

They started tentatively – their trademark passing from the back dangerously pedestrian against the most ravenous press in world football, even allowing for the prospect of a week's liquid refreshment drawing some of its bite.

Ederson made a double save from Mohamed Salah and Roberto Firmino before the former skipped inside Eric Garcia to hit the post.

At that point, Guardiola's mind might have flashed back to a match that was both stinging for him as a proud Catalan and hugely significant in his own career.

After Barcelona surrendered LaLiga to Real Madrid in 2007-08, Frank Rijkaard's side performed a guard of honour for their bitter rivals – albeit at a braying Santiago Bernabeu as opposed to a deserted Etihad Stadium – and were soundly beaten 4-1.

It was an abject embarrassment that rubber-stamped the end of Rijkaard's tenure and Guardiola's elevation from the B team.

His rise has continued more or less unchecked ever since, except for encounters with Jurgen Klopp teams.

A win here does little to remove the stains of an inadequate title defence, but another league loss to follow the error-strewn reverse at Chelsea that gift-wrapped the trophy Liverpool craved beyond all others could have done significant damage.

A creaky defence, all-time leading goalscorer Sergio Aguero crocked, Leroy Sane in Munich never to return. As Salah led blue shirts a merry dance during the opening exchanges, it was easy to see more Mancunian misery unfolding.

But De Bruyne was having absolutely none of that. The Premier League's outstanding player was about to take apart the Premier League's outstanding team.

Even as his team-mates struggled to find their footing early on, two glorious passes released Gabriel Jesus, only for the Brazil forward to mistime his runs.

Guardiola's heart will have been in his mouth when his midfield talisman trod on the ball and landed in a twisted heap for a rare unsuccessful assault on the Liverpool backline.

Hopes of FA Cup and Champions League glory can be launched into the sky with whatever assortment of corner shop explosives you like if City don't have De Bruyne fully fit.

It feels like a trick of the mind that the Belgium playmaker was confined to the margins by two medial knee ligament injuries last term, as City edged Liverpool in that titanic title tussle. He is the heart and soul of a team that has shown too little of those qualities as a collective at times in 2019-20.

The supporting cast sparkled here, though, with Sterling enjoying an overdue night of revelry against his former employers.

According to most versions of events, Joe Gomez handled a rampaging Sterling far more effectively in the St George's Park canteen last November than he did here.

The Liverpool centre-back grappled to foul his international team-mate and De Bruyne slotted the opener from the penalty spot. Gomez could not stop Sterling doubling the advantage and was substituted at half-time.

By that point, De Bruyne had pinged a one-two into the path of Foden for an ebullient finish. There was no let-up early in the second period – Jesus drove at the Liverpool defence and shot too close to Alisson, Sterling saw an effort deflected wide after a run of his own and Virgil van Dijk intervened in the goalmouth to deny Foden.

There was undoubted catharsis in all of this for City, as De Bruyne worked through his full repertoire. Another pass of geometric precision had the insatiable Sterling looking for number four, which arrived as Alex Oxlade-Chamberlain continued his fine scoring run in this fixture in the wrong net.

A headed attempt by De Bruyne to make it five was more Ballon p'Or than Ballon d'Or, but his unrelenting brilliance was the source of relief and pride for City and Guardiola. In the wider context this result can mean little more.

Nevertheless, they have a base camp for the next instalment of a domestic rivalry that has enthralled for three years. "Next season starts today," a defiant Sterling told Sky Sports afterwards.

In Europe, they could be punting for the big prize next month with a two-season ban confirmed. De Bruyne operating in that last chance saloon is a terrifying prospect for anyone.