Ronaldo, said his former club, United, did nothing to deserve their 2-1 win over the Turin side in Wednesday's Champions League tie.
"We dominated the match; we had more chances and we could have finished it off," he said after the game.
"Manchester did nothing to deserve the win. It wasn’t even luck because you make your own luck. It was just our present to them."
The defeat was Juventus’ first in 15 games in all competitions since Ronaldo signed from Spanish giants, Real Madrid, in July.
"The Champions League is special; you can never relax, anything can happen," he said.
The 33-year-old had given Juventus a 65th minute lead with an outrageous first-time volley as he allowed a pin-point through ball from Leonardo Bonucci fall over his shoulder.
However, the visitors hit back twice in the last five minutes, with a Juan Mata free-kick and forced own-goal from Alex Sandro.
"I didn't realise it was a fantastic goal until I saw the replay," the five-time Ballon d'Or winner admitted.
"I was happy for the goal but disappointed because we should have won the game easily by three or four goals."