Jamie Redknapp slammed Lisandro Martinez during Man United's 3-2 home defeat by Nottingham Forest, after his poor defending for the visitors' opener.
Nikola Milenkovic climbed over the Argentine to score his first goal for Forest less than two minutes into the contest.
As well as Redknapp, former United defender Phil Jones gave a critical review of the incident, speaking at half-time during the match.
Jones said: 'First of all it’s a great header. You sense a bit of vulnerability from set-pieces. Martinez is too fixated on his man.
'Diogo Dalot takes a couple of steps towards the ball, maybe gets caught underneath the ball a little bit and almost gets sucked under the ball.'
Redknapp added: 'He’s got to be stronger Martinez, he’s like a little boy there, he just gets bullied. It’s a towering header.'
For the second time in a row under Ruben Amorim, the Red Devils tasted defeat. However, this was the first time that the Portuguese manager has dropped points at Old Trafford, after winning his previous two home games against Bodo/Glimt and Everton.
After 15 games, United now fall to 13th place in the Premier League table as we near the halfway point in the campaign.
They trail rivals Man City in fourth place by eight points, as Champions League qualification seems a more distant target after each game.
At this rate, the 20-time English champions are on track to finish with 48 points by the end of the season, eclipsing their worst points return in the Premier League era by 10; in 2021-22, United finished on 58 points.