Matthew Upson believes Liverpool defender Virgil van Dijk has looked "quite poor at times" during the start of the season.
The 31-year-old has been one of the leading centre-backs in European football over recent seasons and is still yet to lose at Anfield while on the pitch.
However, the Dutch defender has been questioned for his performances in the previous three games, with the Reds still searching for their first victory.
Former England defender Upson believes the Dutch international needs to step up while his team are going through a rough patch.
He told Sky Sports (as per The Liverpool Echo):
"Well I think you're talking about a very accomplished centre back, who's got an amazing reputation, ticks a lot of boxes, but he is a big guy. Liverpool aren't quite firing on all cylinders at the moment and it's going to leave you a little bit more exposed than what you would usually expect. You're seeing that in certain moments that he's finding himself in at the moment."
He further continued:
"When that space is around you, it's about getting out to the ball quickly - getting yourself set. He is a master at assessing 1v1 situations, guiding players into avenues he wants them to go so he can stay on his feet and just shepherd in things where he needs to be."
He added:
"You don't necessarily see him too many times throw himself in the way of balls, go to ground, make last ditch tackles, he's not that type of defender. But he's finding himself in situations at the moment where that's actually now required."
He further said:
"Liverpool aren't in control of games as much as they like so those situations where he's got to go out and affect the ball, he's not really reacting in that way and looks quite poor at times."
What did James Milner scream at Virgil van Dijk after Liverpool conceded a goal to Manchester United
Van Dijk received particular criticism for his performance against Manchester United, where he bizarrely refused to close down Jadon Sancho as he slotted the ball into the net.
This caused an argument on the pitch between Van Dijk and Milner, who had been tricked by a Sancho dummy moments before.
According to The Sun, Milner, the veteran midfielder, shouted at his centre-half:
"You go f***ing out to him!"
Jurgen Klopp's side lost the encounter 2-1 following an incredibly disappointing display at Old Trafford.