Manchester United boss Louis van Gaal has backed Angel di Maria to be a success in the Premier League.

The Argentine, who moved to Old Trafford from Real Madrid last summer, made a sensational start to his career in England.

However, the attacker's performances have dropped in recent weeks and he was substituted at the interval of United's 2-0 win over Sunderland on Saturday.

Van Gaal, however, has insisted that Di Maria must be given time to adapt to life in the Premier League.

"Every player can have that kind of match – Di Maria is not the only player who has suffered a bad day. He can be the best player in the world in the next match, so I think everything is going well. He trained very well and I don't think there is any problem," Van Gaal told reporters.

"I have already explained that the higher rhythm of the Premier League is one of the most important aspects but he also has to adapt to a new culture, a new environment and that is not always easy."

United travel to Newcastle United in the league on Wednesday.