Bruno Fernandes missed a 93rd-minute penalty as Aston Villa won at Old Trafford for the first time in 12 years in a pulsating match.
Kortney Hause had put Villa ahead with a powerful header two minutes from the end of normal time before the defender handled inside the box to present United with a lifeline.
However, Fernandes blazed over high over the bar in front of the Stretford End as United's unbeaten start to the Premier League season came to an end.
Having suffered an early Carabao Cup exit at home to West Ham, United have failed to win - or score - in their past two games before Villarreal's Champions League visit to Old Trafford on Wednesday, in a repeat of the 2021 Europa League final which Ole Gunnar Solskjaer's side lost on penalties.
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