A stunning volley from Ronaldo looked to have won a key Champions League clash for the Bianconeri, only for Juan Mata's free-kick and an Alex Sandro own goal to gift United all three points late on.
The home side had plenty of chances to kill the game in the second half, with the likes of Paulo Dybala and Juan Cuadrado all guilty of missing some golden opportunities, but the introduction of Marouane Fellaini for United seemed to ruffle the feathers of Juventus’ backline.
Ronaldo had no sympathy for his former team at full-time and said Juventus gifted three points to the Red Devils.
“The Champions League is a special competition, where you could be winning, but can’t relax, as anything can happen,” Ronaldo told Sky Sport Italia .
“We dominated the game for 90 minutes, had so many chances, could’ve killed it off three or four times, but we relaxed and were punished.
“Manchester United did nothing to win the game. You can’t even talk about luck, because you have to find your own luck and in this case we just gifted it to them.
“Now we’ve got to lift our heads, as we played really well and are still top of the group.”
The shock victory for United has left them in an excellent position to qualify from Group H, with Mourinho’s side regaining second place from Valencia and now just two points behind leaders Juventus.
The Serie A champions will still expect to progress to the knockout stages, with just one more victory required to guarantee them a place in the last 16.
Captain Giorgio Chiellini slammed his team following the match on Wednesday and claimed that a result like this had been on the cards for some time.
“We want to go all the way and if we are to do that, we must learn from this sort of mistake,” Chiellini told Sky Sport Italia .
“We’ve been threatening this sort of mess for a few games, to be honest, as we get too complacent and run risks that are totally unnecessary.
“Maybe now we’ll get our heads down and focus the way we need to in every single match, taking nothing for granted.”