Former Manchester United centre-back Rio Ferdinand has insisted that Romelu Lukaku must improve if he wants to continue as the club's number one centre-forward.

Lukaku was dropped from United's starting XI for their 2-1 victory over Everton last weekend, before injury forced him out of Saturday's clash with Bournemouth, which Jose Mourinho's side won 2-1.

Marcus Rashford and Alexis Sanchez have both started through the middle in Lukaku's absence, and the Red Devils have looked more fluid in the final third of the field.

Lukaku is without a goal in his last nine games at club level, and Ferdinand has questioned whether the Belgium international will ever be able to become the player that United need him to be.

"You look at Lukaku. Lukaku's goalscoring record is up there, it's fantastic, he scores goals. But in the best teams you need more than that," Ferdinand told BT Sport.

"You need to be able to bring other people into play, you need to be able to complement people in your team, things have to be set up off you.

"At the moment, in a Man Utd shirt, some things break down in Lukaku. And that affects other players in the team, like [Paul] Pogba and [Jesse] Lingard, who want to play off people."

Lukaku has scored four times in 14 appearances for United this season.