Manchester United manager Louis van Gaal has admitted that he is still not sure where Anthony Martial's best position is.

The French international played on the left flank against Crystal Palace, but was unable to manufacture a goal as the Red Devils left Selhurst Park with a 0-0 draw.

However, Van Gaal has insisted that his position, when playing for AS Monaco previously, has made finding the right place for him more difficult.

"We don't know yet because he played always in Monaco as the left winger," Van Gaal told reporters.

"And as a manager I have to see what is the best balance in the team, and that's not so simple. So I have to decide every week also, dependable of the game plan and the opponent, and so on.

"We have played with him in the striker's position, that was not the first time for him, but in Monaco he played always on the left wing."

Martial became the world's most expensive teenager when he signed for United in August.