At 12:36 am on Friday, Rashford quoted a supportive tweet from a fan and added: "I appreciate your support! It is abuse and has been for months. Enough is enough."
"I've a lot of sympathy for Rashy, of course," Ten Hag said.
"Last year, he had a brilliant season. I think the best season in his career, he scored 30 goals. You see what he is capable of.
"This season, he didn't give the performances and people have been very critical. We have to back him and everyone should back him to get back to the levels of last year.
"I think he needs the support. We all know what he's capable of, we all have to support and push him. He can do better than this year. We saw last year when he was really brilliant.
"I think the fans are behind us always. We are entering Old Trafford, I heard the reception. Wednesday was louder than I have heard. Also away: always supportive, backing the team and there is a very good connection between the team and the fans."