Manchester United midfielder Juan Mata has admitted that he never expected Romelu Lukaku to be prolific in front of goal just yet.

The Belgian international joined the Red Devils in the summer from Everton in a £75m deal with the aim of filling the void left behind by injured striker Zlatan Ibrahimovic.

So far, the 24-year-old has delivered by scoring seven Premier League goals, which puts him one ahead of Sergio Aguero, Harry Kane and Alvaro Morata in the scoring charts.

"It's a lot of goals, especially when you come to a new environment," the Manchester Evening News quotes Morata as saying. "I knew he would score a lot but I didn't know he would do it so quick, that's true.

"He gives a lot more to the team, too, but for a striker it's important to score, especially when you see other strikers are scoring and I believe that is what he feels.

"He has started really well and he has been a key part to our good start to the season and he's a good lad, a very humble lad and everyone likes him in the dressing room so we are happy for him."

United sit second in the league table after seven games, level on points with neighbours Manchester City.