For the first time in 284 days, Pep Guardiola tasted defeat in a league game and while this thrilling Anfield night is unlikely to stop Manchester City marching to the Premier League title, it at least offered their beleaguered rivals some hope.
In nine scintillating minutes Liverpool scythed through the City defence, flustering Guardiola’s ball-players into errors and punishing them ruthlessly, scoring three times and racing into a 4-1 lead through goals from Roberto Firmino, Sadio Mane and Mo Salah.
At the end of a week in which Anfield had broken up their Fab Four, with the sale of Philippe Coutinho to Barcelona, the fact the remaining trio all scored in that spell was greeted with delirium.
But City, who had already equalised once after Leroy Sane cancelled out Alex Oxlade-Chamberlain’s early opener, responded as a team at the top of the table should.
As Liverpool’s defence imploded, Bernardo Silva and Ilkay Gundogan scored late goals for City and, with the four minutes of injury-time winding down, the visitors won a free-kick on the right wing which the immaculate Kevin De Bruyne strode over to take.
The tension around the famous old stadium was tangible and the sound of relief when Sergio Aguero dived, unmarked, to head wide from six yards was audible.
A draw would have been par for the course for both clubs’ seasons to date even if, on the balance of the game, it would have been wholly unjust.
But at least, in those nine incredible minutes in which Liverpool scored three times, City finally looked fallible and human for the first time in, perhaps, a year.
Twelve months ago today, City were beaten 4-0 across Stanley Park at Everton, comfortably the worst display of Guardiola’s 18 months in charge of the club.
Since then, City’s only league defeat came in early April when they lost 2-1 at last season’s champions Chelsea; 12 months in which Guardiola’s rivals have looked on in frustration and concern at the powerhouse the Catalan is building in Manchester.
There has been a sense that the combination of Guardiola and the petro-billions that fuel City are in danger of making them an unbeatable force, poised to dominate the English, or even European, game for years to come.
At least Liverpool and Jurgen Klopp, whose six wins against Guardiola in his career are more than any other manager has managed, showed that City can be taken on at their own game of high-pressing, relentless, energetic hunting for the ball, followed by equally ruthless and pacy counter-attacking.
That led to the opening goal, after nine minutes, when Firmino dispossessed Fernandinho in midfield, the ball falling for Oxlade-Chamberlain who surged forwards with one thought on his mind and then unleashed an unstoppable drive across Ederson from 20 yards.
It was the ignition of a fascinating, absorbing contest between two teams, generally trying to play the same way - with a complete emphasis on attack and little concern about what was going on in their own defences.
Aguero slid in and came close to equalising from a De Bruyne cross and, five minutes before the break, a dreadful piece of misjudgement from Joe Gomez saw the young Liverpool full-back fail to intercept Kyle Walker’s crossfield pass properly.
That was all the invitation Sane needed to control the ball on his chest with a deft touch and drill past Loris Karius who should have done more to avoid being beaten at his near post.
As City began to take control at the start of the second half, it appeared that normal service was about to be resumed by the league leaders.
And if Nicolas Otamendi had placed his header a couple of inches lower from a 51st-minute corner, it may well have been. Instead, his effort struck the bar and, a few minutes later, all hell broke lose - albeit hell that City unleashed upon themselves.
On 59 minutes, Oxlade-Chamberlain’s through ball allowed Firmino to chase on, shrugging aside John Stones with contemptuous ease before lifting an instinctive finish over Ederson and in off the far post, where substitute Danilo might have done a better job of attempting to clear.
A mistake by Fernandinho quickly allowed Mane a shot which struck the post and, on 61 minutes, yet another error, this time from Otamendi who lost the ball to Salah, led to Liverpool’s third. There was still much for Mane to do as he received Salah’s pass but his touch and finish from just inside the area were perfect.
City’s woes were not yet over and Ederson, Guardiola’s ‘sweeper keeper’, handed Liverpool their fourth with a poor clearance which Salah controlled and chipped back over the Brazilian from almost 40 yards.
Of course, as poor as City were at the back, they were dangerous in attack which, for neutrals at least, assured Anfield of a thrilling finale.
On 83 minutes, Gundogan’s attempted cross was deflected into the path of Bernardo Silva who poked in from close range and, in the first minute of added time, Gundogan himself reduced arrears to one goal when he controlled Aguero’s chip on his chest before converting.
Karius 5; Gomez 5, Matip 5, Lovren 5, Robertson 6; Can 8 (Milner 79, 6), Wijnaldum 7; Salah 9 (Lallana 87), Oxlade-Chamberlain 8, Mane 8 (Klavan 90); Firmino 8. Subs (not used) Mignolet, Ings, Solanke, Alexander-Arnold.
Ederson 6; Walker 6, Stones 5, Otamendi 5, Delph 5 (Danilo 30, 5); De Bruyne 8, Fernandinho 5, Gundogan 6; Sterling 6 (B Silva 70, 7), Aguero 5, Sane 7. Subs (not used): Bravo, Mangala, D Silva, Zinchenko, Diaz.
A Marriner 6