Manchester United legend Gary Neville has said that Romelu Lukaku will face the toughest test of his United career thus far when he takes on Liverpool this weekend.

Since moving from Everton to the Red Devils this summer, Lukaku has been in sublime form and has so far scored 11 goals in 10 games in all competitions. Considering that the Liverpool defence has been sloppy so far this season, Jose Mourinho will certainly be hoping for Lukaku to exploit them.

Though Neville is a fan of the striker he feels that the game against Liverpool will be a test for him.

"Going away to Anfield is a big test and his service will be more limited so he's now got to show the ruthless streak to win the big games for United," said Neville. "He will be defined by his performances in big matches.

"You're at a club with aspirations of winning things and a world class striker will be defined by trophies and performances in big matches."