Paul Scholes believes Manchester United defender Luke Shaw does not “live his life as clean as he should” but remains an admirer of the youngster’s talents.

Shaw made his first start for United in 219 days on Tuesday night in the side’s Champions League clash against CSKA Moscow.

Despite being partly at fault for the visitors’ only goal of the match, the former Southampton player impressed on his return to Jose Mourinho’s starting XI.

Nonetheless, Scholes has questioned whether Shaw is doing enough to maintain the sort of lifestyle required for a professional footballer.

Speaking on BT Sport, Scholes said: “It's difficult to say as we don't see what goes on behind the scenes. I don't think he lives his life as clean as he possibly should do.

“With his body shape, he looks like a player who needs to be playing every week. We had Wayne Rooney, who was a player if he missed a couple of games you knew, he wasn't looking after himself. He needed to be playing all the time, Saturday, Tuesday, whatever it may be.

“With Luke Shaw, is he going to get a run of 10 games in the team? I'm not sure, the problem he has got is that Ashley Young has been brilliant at left wing-back.

“I hope there is a future for him. A couple of years ago, I thought we were signing the best left back in the world.”

Manchester United vs CSKA Moscow player ratings Show all 11 1 /11 Manchester United vs CSKA Moscow player ratings Manchester United vs CSKA Moscow player ratings Sergio Romero - 7 Helpless for CSKA’s goal. Prevented Alan Dzagoev from scoring a late equaliser. Manchester United vs CSKA Moscow player ratings Victor Lindelof - 7 Didn’t need to be as impressive as he was against Watford and Arsenal but this was another good performance. Manchester United vs CSKA Moscow player ratings Chris Smalling - 7 Should’ve equalised for United but put his header wide at the far post before Lukaku and Rashford spared his blushes. Manchester United vs CSKA Moscow player ratings Daley Blind - 6 His first outing of the season in a back three and wasn’t troubled. Manchester United vs CSKA Moscow player ratings Antonio Valencia - 6 A solid display by the skipper before he was substituted in the second half with Sunday’s Manchester derby in mind. Manchester United vs CSKA Moscow player ratings Ander Herrera - 6 An all-action display by the Spaniard but he lacks Paul Pogba’s quality, which could hinder United in Sunday’s derby. Manchester United vs CSKA Moscow player ratings Paul Pogba - 7 Not his best overall display in recent weeks but provided a lovely assist for Lukaku’s equaliser. Manchester United vs CSKA Moscow player ratings Luke Shaw - 7 Superb going forward in the first half but lost his runner in the build-up to the visitors’ opener. Struggled with his fitness towards the end of the match. Manchester United vs CSKA Moscow player ratings Juan Mata - 8 Capable of producing magical moments and did so numerous times tonight, most notably setting Rashford up for the game’s winning goal. Manchester United vs CSKA Moscow player ratings Romelu Lukaku - 7 The Belgian’s energy has improved in recent matches and he took his goal well. Manchester United vs CSKA Moscow player ratings Marcus Rashford - 8 Caused big problems for CSKA all night and ended his goal drought with a superb left-footed strike.

Scholes maintained that Shaw is the best left-back available to Mourinho but only if and when he is fully fit.

He said: “He is the best left back at the club, he won’t play on Sunday but he showed what he can do.