Manchester United have gotten off to a perfect start in the Premier League this season under Jose Mourinho.
Three wins from their opening three games see the Red Devils joint top of the league, and they're now the favourites to win the title with most bookies.
However, despite the optimism surrounding Old Trafford right now, United legend Paul Scholes is concerned that one particular issue with the current squad will prevent his former club from lifting their first title since 2013 this season.
Speaking in the latest video blog uploaded by Rio Ferdinand to his YouTube channel, Scholes explained to his former teammate that, although he was convinced the team had enough fire power this season, he wasn't so sure about their ability to keep goals out when it came to the big games.
"I'm not sure if they will win it this year," Scholes explained. "But I think under Mourinho they will win the league.
"There's still a few question marks for me for this season. I think a little bit defensively more than anything. I think last couple of years we've worried about goals...
"Daley Blind...great footballer. Brilliant footballer. Whether he's good enough at centre-half in big games? I'm (not sure)."
Blind has been one of the surprises of Mourinho's early tenure at Old Trafford, having impressed at centre-back when many assumed he would make way in the summer.
However, it isn't only the Dutchman who worries Scholes.
"Antonio (Valencia), brilliant going forward. Defensively again, in the big games, I'm not sure."
Scholes is right to suggest concerns about United's defence would make a change from the last few years.
Under Louis van Gaal, the Red Devils were often accused of being boring after failing to create, let alone convert, chances on a regular basis.
However, they did finish the 2015-16 Premier League campaign having conceded the joint fewest goals with 35.
Now, though, Scholes believes that Mourinho's team could be vulnerable at the back as they embrace their attacking options that include Zlatan Ibrahimovic, Wayne Rooney, Marcus Rashford and Anthony Martial to name a few.
Whether the former England midfielder's concerns are justified, only time will tell. However, one thing that will give United fans hope that they can maintain a title push this year is Mourinho's long-standing record of creating teams that are hard to beat.
A trait that has followed him to Manchester so far, with United having only conceded one goal in their first three fixtures.
Check out the full video below...