Danny Welbeck's first-half brace and Tom Cleverley's first Premier League goal in nearly a year were enough for United to stave off the threat of a hat-trick of defeats.
The Scot was furious with Villa's treatment of Januzaj and, when asked if he felt the 18-year-old was being deliberately targeted, said: "Just a bit.
"In every game, I don't know how many tackles there have been on him. That is why I am annoyed with fourth officials and referees. He is definitely not getting protected and before you know it the boy will get a sore one.
"It is terrible what they (the officials) are allowing to go on at the moment. They (opposition players) are queuing up to see who can kick him next.
"(Matthew) Lowton was booked but there were that many tackles on him from different players.
"It is a recurring theme and it's the referees' job to sort it out. You would hope they would recognise that.
"Adnan will just get up, walk away and get on with it. That is one of his biggest attributes."
Unsurprisingly Villa manager Paul Lambert rejected the suggestion his team had set out to intimidate the teenager.
"My team are not a physical team," said the Scot. "We are a young side and maybe sometimes over exuberance gets the better of them but I have never sent anyone out to kick them."