Manchester United manager Louis van Gaal has commended under-fire captain Wayne Rooney for publicly admitting his performances have been below par in 2015-16.

Rooney acknowledged his growing critics following United's 3-1 UEFA Champions League play-off win over Club Brugge, conceding he has made an underwhelming start to the season.

The 29-year-old, who is yet to score a goal in the opening three matches of the campaign, singled out his below-par display at Aston Villa last week, and Van Gaal lauded the United skipper for his honesty.

"It always starts with the player himself, when you are saying publicly that you are so bad, you know that you are very bad at that time, but I think that's fantastic that a player admits that," Van Gaal told reporters ahead of Saturday's Premier League match against Newcastle United.

"But also for me, it's unbelievable because he's one of few players who are saying such things.

"After a few weeks it can bring pressure from the media, he took a risk, but he is very confident that he shall make the goals that we expect from him, and I have that confidence also.

"My standards he knows already, he knows what I want from a striker, how he has to perform, he thinks he can do it and I do also, otherwise I wouldn't put him in that position. Last season he played in all the positions, but I think his best position now is the striker position, and the second position is the number 10.

"He has to admit he was bad so he can improve, if you do not admit you cannot improve."