It is very hard to criticise Manchester City boss Pep Guardiola. The Catalan boss is one of the best bosses of the modern era and his trophy collection proves it. He is also one of my favourite head coaches, mainly from his time at Barcelona.

Sunday’s 3-1 defeat at Liverpool left the reigning champions nine points behind the Reds in the Premier League. While Liverpool are devastating going forward, the game illustrated City’s defensive vulnerabilities.

City failed to sign a centre-back in the summer

Manchester City lost the influential figure of club captain Vincent Kompany in the summer. The Belgian left to become player-coach at boyhood club Anderlecht. The years may have been hard on his body, but he was still crucial to City last season.

His leadership and know-how played a key role in the Citizens winning the title. City really needed to attempt to replace him in the summer. However, Guardiola insisted that he had enough centre-backs in the shape of Aymeric Laporte, John Stones and Nicolas Otamendi.

The fact that Stones had been in and out of favour last season and that Otamendi was not a regular either made the decision not to sign a new centre-back all the stranger.

Then Laporte sustained a serious knee injury at the end of August, leaving City with just two senior centre-backs, neither of whom were first choice last season. They have shown in the last few weeks why they were not first-choice in the previous campaign.

City have quite simply been shocking in defence at times in recent weeks. The current situation shows why they should have signed a centre-back. Laporte is, without doubt, their best centre-back. It is the equivalent of Liverpool losing Virgil van Dijk for long time.

Will not win the title this season

Take away the fact that Liverpool are nine points clear of them, City look like they are a million miles away off winning the title this season. Leicester and Chelsea both moved ahead of the Citizens at the weekend, as the reigning champions dropped to fourth-place.

Guardiola’s team still play fantastic football and have superb attacking players. However, most title-winning teams are built on solid defensive foundations. City in the last few seasons have been outstanding in defence, mostly because they have so much of the ball.

Now though, teams are seeing that City are vulnerable and some are going at them. They no longer look like the formidable team that has dominated the majority of Premier League games for the last few seasons. The fact that they are vulnerable in defence gives teams hope that they can get at the men from Manchester. Previously, they did not look like they had a weakness, now the defensive weakness is there for all to see.

The Liverpool game aside, Wolves, Norwich and Spurs have all scored two or more goals against Guardiola’s side in the top-flight this season. They have also failed to keep a clean sheet in their last four outings in all competitions.

Guardiola should not be above criticism, as nobody is perfect and nobody in this world should be above criticism if they make errors. For me, the Manchester City boss made a giant error last summer by not signing a centre-back.

The decision looks likely to cost City a third straight Premier League title, as the Citizens are now odds of 9/4, with leaders Liverpool now odds of 33/1 to claim the title. Those odds say it all really about the shift in power in the English top-flight table this season.

Should Manchester City have signed a centre-back last summer?