Football hinges on small moments that change or dictate the flow of the game. Kevin De Bruyne found this out the hard way, and must have wished for a time machine at the end of the Manchester City-Chelsea game.

On 57 minutes of Saturday’s game at the Etihad Stadium, the home team were leading 1-0 and the Belgian, left unmarked at the back post and so prolific during his stint at City, had a chance to finish the game off as Jesus Navas’s cross arrived at a reasonable height. But De Bruyne of all people inexplicably managed to hit the crossbar with the goal gaping from four yards out.

Within two minutes the tide had swung in Chelsea’s favour as Cesc Fabregas, nowhere to be seen on the pitch till that moment, pinged a perfect 60-yard pass to compatriot Diego Costa, who effortlessly swatted Nicolas Otamendi aside before burying it past Claudio Bravo.

A game of two halves

Before the game, this column had speculated on whether Pep Guardiola would mirror Antonio Conte’s 3-4-3 formation to try and stop Chelsea from playing the type of football that had seen them notch up seven wins on the trot.

Conte had a pre-match headache of his own as Nemanja Matic’s injury had forced him into changing a winning combination. In came Fabregas, a superior passer but nowhere as combative and established a midfield tackler as the Serb. Meanwhile, Guardiola had done exactly what was expected of him, matching the Italian with a 3-4-3 of his own.

With Leroy Sane and Navas as the wingbacks, and with Ilkay Gundogan and Fernandinho the deepest lying of the midfielders, it gave a licence to the likes of David Silva, De Bruyne and Aguero to go attack.

For the first 45 minutes, City played football that was very un-Guardiola-like, choosing to launch long balls and crosses into the box, especially from the right, specifically targeting Marcos Alonso and Gary Cahill. The plan was simple: stretch Chelsea’s three-man defence of Cahill, David Luiz and Cesar Azpilicueta to its limits and try to exploit the gaps in behind the trio.

When Navas’s crossed was recklessly met by Cahill’s weaker foot, the deflection gave Thibaut Courtois no chance and City had a lead through a self-goal, despite Aguero’s wastefulness in front of goal. Despite surviving a couple of scares, primarily caused by Bravo’s indecision, Guardiola’s gamble had been vindicated. Or so it seemed.

City’s defence in a shambles

Till this game, Guardiola had managed to deflect questions asked of his defence, largely thanks to the efforts of his frontmen who had on most occasions managed to outscore the opposition.

On Saturday, these buried problems came firmly into the spotlight as Chelsea produced a scything counter-attacking display, resulting in three goals being scored from only four shots on target.

Chelsea’s manager showed that his team’s comeback win against Spurs after a half-time team talk was not a one-time party trick, using his 15 minutes to superb effect as an ineffective and struggling Pedro was replaced by Willian, clearly hungry to prove a point to the new gaffer.

After Costa had bulldozed Otamendi for the winner, he heaped further humiliation on the City defence as he received a ball from Hazard, drew the Argentine and then Johnny Stones in before unleashing a perfect through ball to the Brazilian substitute. Willian made no mistake in finishing past Bravo, who appeared more lost than a kid at Willy Wonka’s chocolate factory.

The entire move lasted 11 seconds from start to finish, was breathtaking in intent, and Chelsea had the lead with 20 minutes to go. By the time Hazard had put Alonso’s raking aerial ball into the net with aplomb in the last minute of regulation time, City were finished, their defence of Otamendi, Stones and Aleksandar Kolarov was finished, and so was the game.

There is a growing suspicion that this defence is nowhere near good enough to win the Premier League title, or for a successful run in Europe. Bravo hasn’t looked convincing at all after Joe Hart was jettisoned in favour of the Chilean. There is no point in having a keeper who can start attacks from the back if he can’t stop routine shots, and the City stopper could definitely have done better for Chelsea’s first two goals.

A farcical end

The real drama though came at the very end. The game was lost for City. They should have gone quietly back to the locker room for a dressing down by Guardiola and tried to regroup for the next match.

Instead, Aguero, frustrated all afternoon, put in a cynical and stupid studs-up knee-high challenge on Luiz and the Argentine was rightly sent off by Anthony Taylor, who had a poor afternoon in general and failed to control the fracas that followed, much like most of the game.

In a display of pathetic professionalism, tensions from both sides boiled over as substitutes Nathaniel Chalobah and Kelechi Iheanacho got involved, as did Fabregas and Fernandinho, the latter being sent off as well while the two Chelsea players were lucky to escape with yellow cards. Guardiola, who had a meltdown of his own and was seen sarcastically applauding the referee moments before the brawl broke out, had to intervene and pull Iheanacho out before a third City player got sent off.

As a result, not only are City four points behind the Blues, but will also be without two of their most important first-team members for upcoming fixtures against Leicester, Watford and Arsenal. Aguero, having already being suspended once this season for violent conduct, will also miss an additional game against Hull City. A situation entirely unavoidable and most unfortunate for City and Guardiola, who haven’t won any of their last four home games in the league.

As for Chelsea and Don Conte, they won all the important battles on the day as the Italian manager made the right changes and bested his Spaniard counterpart, who is yet to beat Chelsea in regulation time at six attempts. Costa won the battle of the forwards against Aguero.

With games against West Brom, Sunderland, Crystal Palace, Bournemouth and Stoke before a new year trip to Spurs, Chelsea could be sitting pretty at the top of the table by the end of the year. Having won eight games in a row, including wins against Manchester United, Spurs and now City, their position as leaders, if it materialises, will be fully deserved.