The visitors stunned the home crowd in the fourth minute when City keeper Joe Hart could only parry Giuseppe Rossi’s shot, sending the ball straight to the feet of Cani who slid the ball home.

City pushed for the equaliser with chance after chance against a side who barely ventured forward again but had to wait until the 43rd minute to get off the mark when Villarreal defender Carlos Marchena put the ball past his own keeper.

The Premier League leaders, who have struggled to match their domestic form on the European stage, had looked to be heading for just one point before Aguero slid the ball home deep in stoppage time to send the Etihad stadium wild.

The result puts City on four points from three games, with Villarreal yet to score a point. Bayern Munich head the group on seven after a 1-1 draw at Napoli who have five.