Despite dominating possession, the hosts were frustrated, and almost defeated, by the impressive Serie A outfit, as their Champions League debut failed to go according to plan
Defender Aleksandar Kolarov rescued a point for Robero Mancini's men with a fine free-kick which cancelled out Edinson Cavani's 69th minute opener.
The English Premier League side recalled Edin Dzeko to the starting line-up after resting him against Wigan, with Carlos Tevez taking a place on the bench as Mancini made five changes.
Napoli, meanwhile, were able to field a full-strength side, with their feared triumvirate of Marek Hamsik, Ezequiel Lavezzi and Cavani all playing.
The home side looked ominous right from the start, showing off some clever passes, culminating in Samir Nasri flashing wide with the first chance of the night having been backheeled the ball by Dzeko.
But the visitors demonstrated why they were one of Serie A’s most exciting sides last season when they broke in the 17th minute. Argentine forward Lavezzi snuck past Vincent Kompany and into the box and deftly shot past Joe Hart, only for the ball to cannon off the crossbar.
City should have taken the lead when Yaya Toure was gifted the ball straight from a Napoli corner, bursting forward through the middle and feeding Aguero on the right. The striker danced inside the penalty area before teeing up Toure who arrived late, but the Ivorian leant back just a little too much and crashed his shot against the bar.
After the resumption, Napoli were quicker out of the blocks, and Hamsik was supplied at the right post thanks to great work from Juan Zuniga on the left, but his side-footed shot was cleared off the line by Kompany.
City ground to a halt in the face of the Italians’ resolute defending, and the home side’s party was well and truly crashed as Napoli got what had seemed was coming to them when Cavani was played through with a perfect pass by Christian Maggio, finding himself one-on-one with Hart before slotting beautifully between his legs to give his side the lead.
The shock sparked the hosts into life and again hit the woodwork. Nasri burst through the left and supplied Aguero with a low cross, but the Argentine could only flick onto the bar.
In the aftermath, the Italians conceded a free-kick just outside the area in the 74th minute. Kolarov stepped up and blasted a devastatingly simple shot into the top corner to reignite his side.
Reminded of their early supremacy, Mancini’s men lit up once more, with Dzeko attempting an ambitious turn-and-shot having been found by substitute Adam Johnson. But in doing so, he had ignored the perfectly positioned David Silva, who was awaiting a pass for a tap-in.
Both teams sought a winner in the final minutes but neither could make the breakthrough and the match ended all square.
Matchday two sees Manchester City travel to Germany to face Bayern Munich, while Napoli host Spaniards Villarreal.