Wayne Rooney's struggles are down to Louis van Gaal's system at Manchester United, according to Charlie Nicholas.

Rooney has gone 10 games without a goal, despite being moved into the central striker's position following spells at No 10 and as a deeper-lying midfielder.

But despite criticism over his sluggish performances so far in the Premier League, Soccer Saturday pundit Nicholas believes the 29-year-old - who last found the net on April 4 - is the victim of a system that leaves the centre-forward too isolated.

"It's the system that's the problem, it's a Van Gaal system," said Nicholas, speaking ahead of Wednesday's Champions League play-off decider in which United hold a 3-1 lead over Club Brugge.

"I remember, way back, when Arsenal played Barcelona at Wembley and Van Gaal was their manager. They played Rivaldo wide left, [Patrick] Kluivert through the middle and Figo wide right. He likes to stretch the game. That's the way he plays to bring space into account but this means the centre-forward can be quite an isolated figure.

Wayne Rooney has not scored for Manchester United since April 4

"Rooney is not a target man. He can play centre-forward but he can't play as a target man and at the moment his service is poor.

"Until they identify the midfield - whether it's going to be [Juan] Mata, Memphis, [Ander] Herrara, or whoever it is going be, the two holding players in midfield will not suit Wayne.

"It's the system, it's not Wayne's fault.

"If you don't get quick support to him and he only gets occasional passes he's out of the game.

"Wayne Rooney for me needs challenging. If I was his manager every single week I'd be challenging him mentally. What are you thinking? How can you play this week? What about dropping back 15 yards. Challenge his mind; Wayne loves a challenge.

"He's trying as hard as he can but the style just doesn't suit him."

Marouane Fellaini scored a late third to ensure United take a 3-1 lead to Belgium

Van Gaal has revealed he will also use Marouane Fellaini - who scored United's third against the Belgians at Old Trafford last week - as a striker this season, whether as the main forward or in the No 10 role.

"He can play in a 9 position and in a 10 but also 6 and 8 but this year he shall play more 10 and 9 than 6 and 8 because there [in midfield] we have more players," Van Gaal said.