So far this season, City have managed to mask their left-sided frailties, with Pellegrini’s more astute tactical brain tweaking the problem.
But as with any patch-up job, it is only going to last until pressure is applied and Pellegrini was faced with that frightening prospect when Barcelona rolled into town for last night’s Champions League last 16 first-leg encounter.
The pace and trickery of Alexis Sánchez, supplemented by the overlapping runs of Dani Alves, ensured that Barcelona possessed the tools to capitalise on City’s left-sided weakness, so Pellegrini’s answer was to play both Clichy and Kolarov in the same team in an effort to bolster that area of the pitch.
Clichy and Kolarov appear together as Liam and Noel Gallagher nowadays and their chemistry is little better.
Neither can defend in the manner of a typical left-back and their positional sense is also questionable when in the defensive third.
On the plus side, Clichy benefits from genuine pace while Kolarov’s ability from set-pieces is without question.
Their task against Barcelona, however, was to offer defensive solidity at the same time as pushing Alves back and frustrating Sánchez.
For all the danger posed by Lionel Messi, Pellegrini has seen the Argentine up close often enough to realise that attempts to stop him are futile and the only way to nullify him to stifle those around him.
Neither Clichy nor Kolarov were up to the job asked of them, though, and the left-side issue was exposed to an even greater extent with Martin Demichelis deployed to the left of captain Vincent Kompany at centre-half.
Demichelis, an eleventh hour signing from Atlético Madrid last August, suffers from unfair criticism at times due to his lack of pace and pony-tailed appearance.
He can pass, is comfortable on the ball and is well-known to Pellegrini having performed well for the coach at Malaga, but he certainly had an off-night against Barca, which was capped by his red card for fouling Messi and conceding a penalty.
Sadly for City, Clichy, Kolarov and Demichelis against Barcelona was a footballing Bermuda Triangle.
In the first-half, a slip by Clichy after losing possession was followed by a misjudgement by Demichelis, but the home side survived until half-time simply because of the Herculean efforts of captain Kompany.
City’s defensive plan unravelled in the 53rd minute, though, when Demichelis was dismissed by Swedish referee Jonas Eriksson for fouling Messi.
It was a close call as to whether the foul was committed inside or outside the penalty area, but as soon as Messi received the ball, his former Argentina team-mate was already doomed due to his position.
Immediately, Twitter exploded with the gag that Barcelona will now appeal Demichelis’s red card in order for him to be able to play in the second-leg at the Nou Camp in three weeks. Harsh.
Still, Pellegrini was now forced to make a switch, with Kolarov replaced by Joleon Lescott, leaving Clichy to deal with Alves and Sánchez on his own.
The former Arsenal defender appeared exhausted by his nights’ work, perhaps explaining why Tata Martino introduced Neymar in place of Sánchez in order to chase a second goal which would surely kill the tie.
And it duly came, two minutes from full-time, when Barca once again pinpointed City’s left.
Neymar and Alves simply danced around the flailing Clichy before Alves passed the ball past Joe Hart and into the net.
Game over, tie over.