Manchester City vs Liverpool: 5 things we learned as Sergio Aguero and co lay waste to 10-man Reds

Manchester City 5 Liverpool 0: Pep Guardiola's side strike an early blow in the Premier League title race as Liverpool live to rue Sadio Mane's early red card

Sergio Aguero opened the scoring thanks to a sumptuous through ball from Kevin de Bruyne (AFP/Getty Images)

Manchester City struck an early blow in the Premier League title race as they ran out easy winners over Liverpool in a match that was transformed by the controversial first-half sending off of Reds forward Sadio Mane.

City’s opener came somewhat against the run of play, with Kevin de Bruyne playing a sumptuous through ball to Sergio Aguero who shimmied and deceived Simon Mignolet to leave himself with an easy tap-in.

But big moment of the game came before half-time as Mane, put through one-on-one, was shown a straight red for a high boot to Ederson, which saw the goalkeeper stretchered off and sent to hospital.

From then on there was only going to be one winner. Gabriel Jesus made the advantage count immediately as he doubled City’s lead with a header from man of the match De Bruyne’s assist and added a third courtesy of a generous assist from Aguero when he could surely have scored himself.

City had two other goals disallowed either side of half-time and eventually added a fourth and a fifth as substitute Leroy Sane linked up with Benjamin Mendy for a tidy near post finish before curling in a superb 25-yard strike in injury time.

Here are five things we learned...

1. VAR will never kill the debate

Ederson is caught in the face by Sadio Mane's raised foot (Sky Sports)

The big debate after this game will surely be dominated by whether Mane should have received red for his challenge on the City goalkeeper.

Mane's boot was high and contact with Ederson looked nasty but opinion was still divided on commentary and on social media as to whether it was worthy of a sending off - particularly with the rules - was it "serious foul play" or merely "reckless"? - being seemingly open to interpretation.

While the rest of the world has the benefit of endless slow-motion replays and different angles of the incident, referee Jon Moss had just one.

There are many benefits of video assistant referee (VAR) technology, but cooling debate in a situation like this is not one of them. Had Moss been afforded the option to change his mind after viewing a replay, he would still have 50 per cent of football fans haranguing him for choosing a different course of action than the one they believe was correct.

The best solution to this problem would be for the referee to come out and explain his decision to the television cameras after the game - sadly, that happens all too rarely.

2. South American swagger

Questions had been raised ahead of the new season whether or not Pep Guardiola would be able to accommodate both Aguero and Jesus in his starting XI, but today's display suggested the pair might just have a bright future together.

It was Aguero who opened the scoring, rounding Simon Mignolet in the 24th minute to hit home his 124th league goal and cement his place in the history books as the Premier League's all-time highest ever non-European goalscorer. The goal was yet another reminder of the forward's inherent worth to City. Cool, calm and collected, Aguero acted with the elite level of professionalism and goalscoring know-how that has defined his impeccable career down the years.

Against the experience and maturity of his teammate, Jesus sparkled with a youthful verve and confidence that once again reaffirmed his class. The Brazilian bagged himself a well-taken brace, with the latter notably coming a result of an Aguero assist. Two on one, the Argentine set up his South American counterpart with a selfless lay-off that suggested this could well be the early beginnings of an irresistible front-line partnership. If both can continue to deliver in these sort of high-intense, crunch fixtures then there's no reason why they don't each deserve a spot in Guardiola's starting XI.

3. Defensive woes from both sides are inexcusable

Nicolas Otamendi was lucky to be on the winning side (Getty)

For all the talk of transfer windows, when they close and the rights and wrongs of the deadline, the biggest issue for both of these sides remains that they are a central defender short.

That is nothing to do with the length of the window nor its fermeture, rather it is a damning indictment of the way either club went about its business this summer.

Nicolas Otamendi's performance against Liverpool was all the evidence necessary to understand why Manchester City pursued Jonny Evans during the off-season. But they left it too late and, ultimately, didn't push on to complete the deal as they couldn't shift Eliaquim Mangala. With Guardiola seemingly determined not to start with Mangala, it leaves City a defender short which, given their resources, is inexcusable. It's also the second consecutive season they've done it.

Liverpool started Ragnar Klavan ahead of Dejan Lovren as the partner for Joel Matip. Klavan was all at sea once again and while he can do a job against some of the Premier League's lesser lights, always seems to be exposed against the division's elite.

The Reds had one target and one target only in central defence and it was hardly a secret, but Jurgen Klopp's refusal to compromise and buy a plan B when the deal for Virgil van Dijk became impossible could be costly in terms of their title ambitions.

Given Liverpool emerged from last season knowing their backline was holding them back, the decision to exit the window without having really remedied that makes every defeat feel self-inflicted.

4. TAA needs to get Prem smart

The youngster will have to learn fast if he continues to be isolated by opposition sides (Getty)

Trent Alexander-Arnold has enjoyed an eventful start to this season, scoring a brilliant free-kick against Hoffenheim in the Champions League play-off and scooping up many well deserved headlines for that eye-catching performance.

The youngster has talked up his hopes of captaining his club in the future but he looked a long, long way off that here as the experienced talents of De Bruyne and Benjamin Mendy down City's left flank gave him a torrid afternoon.

The right-back was given a stern talking to by the referee early on and then booked for a naive foul on De Bruyne shortly afterwards which left him worrying about a second for the rest of the afternoon.

It appeared he was targeted by Pep Guardiola's men - a fate he may suffer more than once this season against the better sides - and he will have to learn fast, especially if his central defensive colleagues and right-winger (in this case Salah) leave him so isolated.

5. The grass isn't always greener

Alex Oxlade-Chamberlain came on as a second-half subsitute with Liverpool's cause already all-but lost (Liverpool FC)

In a twist of irony that will have come as a delight to Arsenal fans, Alex Oxlade-Chamberlain found himself consigned to the bench for the opening 45 minutes of today's clash - before succumbing to a heavy defeat alongside his hapless teammates.

The Liverpool new boy had said in the build-up that he left Arsenal for Anfield in the hope of reaching his potential and thriving under Klopp's bombastic, gung-ho approach - but if Saturday's game is anything to go by, he looks to have arrived two weeks late.

By the time he entered the fray in the second half, Liverpool's cause was all-but lost. As expected, the Englishman added very little to the game as he struggled to assert his authority from a central position in the Liverpool team. Given the circumstances of the match, Oxlade-Chamberlain was always going to be fighting a losing battle but this was a stark reminder that the grass ain't always greener on the other side.