Cristiano Ronaldo marked his return to Old Trafford with a win as his Juventus side outclassed Manchester United to move five points clear at the top of Champions League Group H.
The former United star helped to set up Juve's winner in the 17th minute, with his cross reaching Paulo Dybala who finished from close range.
The Italian champions had several chances to extend their lead during a first half where they were completely dominant, managing 10 shots to United's one and enjoying 70% of possession.
It was a frustrating night for United boss Jose Mourinho, who was taunted by the away fans as he saw his side suffer only their second home European defeat since March 2013, when Ronaldo scored Real Madrid's winner.
The two sides will meet again at the Allianz Stadium on 7 November, when a win will send Juve into the last 16.
United remain in second place, with their hopes of making the knockout stages boosted by Valencia's draw with Young Boys earlier on Tuesday.