Rio Ferdinand believes Louis van Gaal's decision to return Wayne Rooney to his favoured attacking role has led to the Manchester United's upturn in performance levels. Writing in his column in The Sun ahead of the Manchester derby on Sunday, Ferdinand, now at Queens Park Rangers, revealed his belief that Rooney playing as a striker is fundamental to United hitting fifth gear. He praised Van Gaal for moving his captain further up the field after a spell in the centre of the pitch at the start of the year but admitted the return to form and fitness of Ander Herrera, Marouane Fellaini and Michael Carrick has also been important. Rio Ferdiand (right) believes that Manchester United are at their strongest with Wayne Rooney in attack . Rooney (right) has helped inspire United to their best displays of the season by leading their attack . Ferdinand praised Van Gaal for moving Rooney further up the pitch, after playing him in midfield . 'Carrick returning has obviously helped but the biggest of the lot is playing Wayne Rooney up front,' Ferdinand wrote. 'Wayne's a goalscorer. He has United's goals record in his sights and the side functions better when he is there. 'The fact is that United need a fit Rooney up front.' United have only lost twice in the Premier League in 2015 but the majority of their eight victories since January were not executed with the conviction in display that Ferdinand regularly produced in the team under Sir Alex Ferguson. That was until they overturned Tottenham 3-0 at Old Trafford in March, following up the emphatic result with a commanding performance at Anfield, where they beat top-four rivals Liverpool 2-1. Ferdinand said that victory reminded him of the team he used to be a part of. 'It's about more than just results,' Ferdinand wrote. 'The performance against Liverpool was the Manchester United of old. Rooney (left) receives tactical instructions from Ryan Giggs (centre) in the United game against Liverpool . Ferdinand also pointed to the return of midfield player Michael Carrick (left) as a help to United . Rooney will lead United against Manchester City in the Premier League's stand-out fixture on Sunday . 'My mates said to me 'That's the Manchester United I remember.' It was a sign they were on to something.' United's 3-1 victory over Aston Villa last weekend, combined with Manchester City's 2-1 defeat at Crystal Palace on Monday, saw Van Gaal's team move above City by a point and into third.
Rio Ferdinand says Manchester United need Wayne Rooney in attack .
He believes Rooney's form has been key to their upturn in performances .
Ferdinand said United's 2-1 win at Anfield shows they are 'on to something'
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