Gabriel Jesus celebrates with Sergio Aguero

Ten-man Liverpool were also knocked off course as they lost their first match of the season – and to a title rival too.

Jurgen Klopp was derailed, too, as he suffered his first defeat to City in five matches as Liverpool manager.

Sergio Aguero opened the scoring before Gabriel Jesus and Leroy Sane scored two each to give their side a significant victory.

It was a match in which Manchester City had too much firepower for a man-down Liverpool.

And to make matters worse for Liverpool, Sadio Mane was sent off for a dangerously high challenge on keeper Ederson Moraes in the 37th minute.

It all went wrong for Liverpool, unbeaten against all their main rivals last season, with yet-to-lose City so impressive.

The scoreline could have been even worse for Liverpool as City had two goals disallowed and Kop keeper Simon Mignolet made a series of saves.

It was a dramatic, incident-packed day at The Etihad. But at the start, it was almost a case of who was not playing, rather than who was.

No Vincent Kompany, no Raheem Sterling and Bernardo Silva on the bench. No Alexis Sanchez, either, for that matter as Arsenal refused to sell him to City boss Pep Guardiola.

For Liverpool, no Philippe Coutinho, no Adam Lallana, no Nathaniel Clyne and Alex Oxlade-Chamberlain, at first, only on the bench.

But there was always going to be enough talent in both sides to ensure an open, attacking game.

At times, in the early stages, City were at full stretch to cope with Liverpool’s lively attack. Roberto Firmino had an early opportunity from Jordan Henderson’s fine delivery, but the Brazilian failed to turn the ball home at the far post.

But City, who had gone close earlier when Fernandinho was denied by Mignolet, surged into the lead in the 25th minute.

Kevin De Bruyne’s classic defence-splitting pass sent Aguero through in a one-on-one situation with Mignolet.

The City striker went round the Liverpool keeper and rolled the ball home with a right-foot finish.

It was the Argentina marksman’s 124th Premier League goal, making him the competition’s highest non-European scorer.

Both keepers then made fine saves – Ederson from Mo Salah and Mignolet with his feet to deny Jesus and John Stones.

But the real drama started in the 37th minute and continued through seven minutes of added first-half time.

Mane was sent off for a high challenge on Ederson, his raised boot hitting the City keeper flush in the face.

After lengthy treatment, Ederson was carried off on a stretcher, with a brace supporting his neck.

There was still time before the interval for Jesus to score legitimately with another header, the cross once again supplied by the immaculate De Bruyne. City had the ball in the net again in the 53rd minute through Aguero, but it was ruled out by the assistant referee’s flag.

Within seconds, though, they did make it 3-0 as Aguero raced clear and unselfishly set up Jesus for a comfortable finish.

And 13 minutes from time, substitute Leroy Sane got in on the act, neatly firing home Benjamin Mendy’s cross.

Sadio Mane saw red for this sickening collision

Mignolet looked to have made sure it was not more embarrassing for Liverpool near the end with a sprawling save to keep out Aguero’s effort.

But there was still time for Sane to curl home a brilliant left-foot shot in added time to make it five and equal the heaviest defeat of Klopp’s managerial career.

Guardiola said: “To have 11 versus 10 for 50 minutes is a good advantage. The game was equal when it was 11 against 11.

“But against Everton recently, we were better with our 10 to their 11.

“It’s a long time since City have been able to beat Liverpool and in Kevin De Bruyne we have the complete player. We are lucky to have him with us.”

Klopp, meanwhile, said that Coutinho was in his plans to return against Sevilla in the Champions League on Wednesday.