Manchester: Manchester United’s record goalscorer Wayne Rooney says Romelu Lukaku has to be mentally strong to succeed at the Old Trafford club.

The 24-year-old Belgian striker last week joined Manchester United from Everton on a five-year contract for a reported transfer fee of 75 million pounds (Dh360.7 million).

“You’ve got to be strong enough mentally to accept the challenge, United are a football club that demands success. Romelu has to be strong enough to take up that challenge,” Rooney, 31, was quoted saying by Fox Sports.

Rooney, who left Old Trafford to rejoin his boyhood club Everton the same weekend as Lukaku switched sides, holds the record of being United’s highest goal scorer with 253 goals.

“Playing for Manchester United is a test of character,” Rooney said.

“Hopefully, Romelu has got people there who will give him the right guidance and get the best out of him,” he added.

“There are standards that you have to keep when you are at Manchester United. That came from [former manager] Alex [Ferguson] when I went to United and it was passed down through the likes of Giggsy [Ryan Giggs], Gary Neville and Scholesy [Paul Scholes].”

“Over the last few years, it was down to me and Michael Carrick to keep the new players maintaining those standards.

“That has been more difficult over the last few years, with some of the players who joined the club. There are traditions at United that have to be maintained,” Rooney said.