Manchester City's Champions League campaign got off to a disappointing start with a home defeat by last season's runners-up Juventus.
City, who have struggled to make a serious impact in the Champions League and have never won their opening home game in the group stage, looked to be on course for victory when Juventus defender Giorgio Chiellini headed into his own net under pressure from Vincent Kompany.
The Italians protested furiously that Chiellini had been fouled but then produced an impressive response to come from behind and close out the win.
Paul Pogba's superb ball allowed Mario Mandzukic to steal in behind Eliaquim Mangala for the equaliser, then Alvaro Morata pulled substitute Nicolas Otamendi - on for Kompany - out of position before curling a precise left-foot finish beyond City keeper Joe Hart for the 81st-minute winner.
Raheem Sterling had two big opportunities for City but wasted both as Manuel Pellegrini's side find themselves on the back foot once more in the Champions League.