Manchester City were beaten 3-1 by Nottingham Forest at the City Ground, leaving them six points adrift in the Premier League title race heading into the international break

The old adage is that defence wins championships, so perhaps it's no surprise that Manchester City's Premier League title tilt is faltering amid a shaky foundation.

City slipped to a third successive Premier League defeat at Nottingham Forest on Saturday evening, shipping three goals as their run without a clean sheet extended to nine games in all competitions.

Individual errors have contributed significantly in recent weeks but the Blues' backline looks brittle and only seven top-flight sides have conceded more goals in the Premier League than second-placed City this term.

That should be cause for alarm for Enzo Maresca, and the signs were there even during the seven game winning start to the top flight. City's firepower bailed them out on more than one occasion but that the stats were not sustainable and the Blues have so far been short of answers.

Maresca has fielded four different back fours in the last four Premier League games and the last time he fielded the same defence in successive matches was for the wins at Porto and Manchester United in September.

There has been more consistency in the Premier League but there have still been four different City defensive selections in 10 games.

Maresca went with his most trusted top flight selection at the City Ground with Khusanov at right-back, Dias and Guehi in the middle and Gvardiol at left-back. That's been the City boss' selection in four Premier League fixtures this season but a double defensive change at the break highlighted how it wasn't working.

Gvardiol has had a shaky start to the season and looks short of his best form, while Khusanov has performed significantly better at centre-half than right-back while the Dias and Guehi combination has not looked at all secure.

In their last four starts together, one of that pair has been taken off at half-time - with the skipper withdrawn when City were trailing 3-0 at home to PSG in the Champions League, while Guehi was hooked when the Blues were one down at Villa and 2-0 behind against Forest

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There have been individual errors leading to goals in each of the last three top-flight fixtures - all defeats - against Villa, Brighton and Forest, while goalkeeper Gianluigi Donnarumma was at fault for a goal against RB Leipzig in midweek.

In recent weeks the City defence has looked fragile and short of confidence. Perhaps Maresca's chopping and changing, both during games and week to week, is not helping and the Italian has seemingly yet to settle on his favoured back four even if the Blues boss cannot legislate for some of the individual mistakes he is watching.

But between manager and squad a solution must be found if City are to challenge for silverware this season. So far the Blues have been found wanting.