Paul Scholes urged Manchester United to sign Leicester City star Wesley Fofana to strengthen their bid for the Premier League title.
The Red Devils beat Burnley 1-0 on Tuesday to go three points clear at the top of the Premier League table ahead of a vital clash with defending champions Liverpool on Sunday.
United manager Ole Gunnar Solskajer has settled on a centre-back pairing of Victor Lindelof and Harry Maguire for the majority of the campaign - and the duo have impressed for the most part.
But Lindelof was unavailable to face the Clarets with a back injury and Eric Bailly came into the line-up in his absence.
While Bailly helped United keep a clean sheet at Turf Moor, Scholes remains concerned the Ivory Coast international is too "rash" for a title-chasing side.
Instead, he would like to see Fofana come to Old Trafford, only months after joining Leicester from St-Etienne for £36.5million last summer.
"When we won titles, so many of our wins at Liverpool were 1-0 or 2-1 after having to dig it out for 80 minutes," 11-time Premier League-winner Scholes told ESPN .
"You accept you’re going to have days like that against the top teams, when you don’t dominate the game and have to battle to stay in it.
"You have to be able to defend properly and withstand the opposition’s attacks, but I’m still to be convinced that this United side can do that.
"As a back four, I worry about how good they really are.
"At full-back, Aaron Wan-Bissaka is just about defending, which is fine for a game at Liverpool, but I’m not sure what Luke Shaw brings to the team.
"In the middle, Ole still has to find Harry Maguire’s best partner. Eric Bailly has pace, but he is rash and picks up too many injuries.
"Victor Lindelof plays the position better and seems to be Ole’s preferred option, but again, he is not totally convincing.
"If I was Ole and could sign a defender this month, I’d go for Wesley Fofana at Leicester. He’s only 20, but he has been outstanding and he has the potential to be anything he wants to be.
"United have done okay at the back this season, but they have been exposed when playing against the big teams and that’s another problem they need to solve."