Liverpool were destroyed for 45 minutes, but while Jurgen Klopp’s side have Mo Salah they will always have hope

For 45 minutes, Manchester City were merciless.

Pep Guardiola had reverted to first principles at the Etihad, essentially selecting a team of midfielders, with Kompany and Aguero left out. In doing so, he ensured Liverpool would suffer, not through the aggression of Kompany or the goals of Aguero, but through the endless, sadistic movement of the ball and players.

But there was one mercy. At the end of 45 minutes, City had only one goal, and they began the second half with Guardiola watching from the stand, dismissed for his understandable complaints that City had wrongly had a second disallowed.

Liverpool had watched for 45 minutes. They had witnessed this creation of staggering beauty and bewitching complexity unfurled in front of them and then, like Indiana Jones pulling his gun after the swordsman had magnetically flashed his blades, Liverpool shot City down. And, inevitably, it was Mo Salah who knocked City out.

Salah, half-fit and marginalised for much of the game, delivered his own moment of wonder to end the tie, picking up the ball after Ederson had closed down Sadio Mane as he moved through on goal. From that moment, Salah's preternatural ability to create a world of calm when all around him is chaos ensured Liverpool would go through, As he lofted the ball into the City net, all of the home side's staggering beauty had been in vain.

And Liverpool could breathe. ‘Where’s your European Cups?” their fans sang after Roberto Firmino’s goal had made their place in the Champions League semi-finals inevitable. Nobody thought City could score six.

For a while it looked as if they could score whatever they wanted. Jurgen Klopp’s achievement in taking his side to the last four in the Champions League highlighted all he has already achieved at Anfield.

If Liverpool had won the tie during the first 45 minutes at Anfield a week ago, they needed to find some resolve during the second half here at the Etihad and in doing so, they took down a team which, in the first half, produced a stunning display of fast, relentless football.

In the second, Liverpool found many things that had been absent in the first, most importantly Salah, but after that a midfield. Gini Wijnaldum was more involved in the first five minutes of the second half than he had been for all of the first period, when Liverpool seemed resigned to being witnesses to this great City resurgence. For 45 minutes, that was what it looked like. All everyone had said about the debilitating effect of Anfield last week and the Manchester derby on Saturday seemed like simply more for scepticism for Guardiola to rise above.

After Gabriel Jesus's early goal, Liverpool were anxious, overhitting passes and making wild challenges as they tried to play for time, but they never seemed to get time on their side.

City's inventiveness never seemed to stop. If Pep had selected an extended midfield, the ground staff kept the ball moving too, returning it so quickly that Liverpool could never recover.

Jesus's goal highlighted these differences. Raheem Sterling had knocked Virgil Van Dijk off the ball and Fernandinho had quickly found Sterling who was in the space Van Dijk might have been in a parallel -and, from a Liverpool point of view, happier - universe.

But he wasn’t there so Sterling squared to Jesus and City had the lead. City still needed a couple more but Liverpool slumped like they had glimpsed an unwelcome, bitter future.

Their midfield, which was never going to get on the ball like City’s, shrunk worryingly as Kevin De Bruyne, David and Bernardo Silva and the rest toyed with them, passing the ball endlessly, playing some sort of cruel but beautiful version of football as it might have been reimagined by Dr Seuss.

It was easy to forget that it was City, not Liverpool, who were on the edge. They needed two more goals and if they conceded one, the task would have seemed too much, although it was hard ti imagine anything being too much for City as they played like this.

Bernardo Silva had a shot off the post and Leroy Sane's goal was ruled out for offside but then things changed.

Alex Oxlade-Chamberlain went close before half-time and once Liverpool got on the ball in the second half, they remembered their own virtue. Klopp has created a side of remarkable purpose with a player in Roberto Firmino who is always there if you need him and another like Salah whose season has been extraordinary. In the second half, they showed that. When Salah scored, all that City had done in the first half seemed to stop. There was no more bewitching music. There was no music at all. Suddenly, City were tired and drained. Suddenly they were mortal. Liverpool had ground them down. Jurgen Klopp's side had shown no mercy.