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Aguero's thwarted run across the box eventually led to Kolarov's 10th-minute strike from the left side of the penalty area, which took a deflection off Alan Hutton on its way to smashing the woodwork.
The same City pair were involved again just prior to the half-hour mark when the Serbian left-back crossed for the Argentine striker, whose flick header had Guzan beaten but narrowly missed the target.
Kolarov, James Milner and Edin Dzeko all came close in the final moments prior to the interval as Villa defended well to hang on to half-time parity, with Nathan Baker producing a couple of crucial blocks to keep the score at 0-0.
However, with Gabriel Agbonlahor having been forced to withdraw shortly before kickoff with illness and fit-again striker Christian Benteke only on the bench, the home side struggled to create chances of their own.