Manchester United hero Roy Keane tore into Liverpool star Fabinho's defending of the first goal during Thursday night's game, and warned the Brazilian midfielder lacks "football intelligence".
Liverpool went behind after just ten minutes at Old Trafford as Bruno Fernandes bagged his 28th goal of the season.
The Portuguese star took advantage of a defensive mix-up from the visitors and curled a shot towards goal with the outside of his right foot.
Nat Phillips slammed the ball past Alisson as he attempted to block the shot and clear the ball from the box, but he wasn't the player Keane was unhappy with.
The outspoken pundit picked out Fabinho for criticism and claimed he was lacking football intelligence for failing to track back properly and get close to Fernandes.
Keane explained to Sky Sports that the midfielder should have moved to get himself in front of the ball despite Liverpool's numerical advantage inside the penalty area.
"It was no surprise when they got the goal, Liverpool seemed to be really open for the first 20-25 minutes," he said.
"As dangerous as they were going forward, you thought it's only a matter of time [before United score].
"[Marcus] Rashford, again, a ball down the side and no danger from Liverpool's point of view.
"It was poor defending from Liverpool's point of view.
"Fabinho, getting back in, you look where Liverpool are and they do have the numbers, it's about decision-making, football intelligence.
"Wan-Bissaka does well but look at Fabinho, he just runs past the ball.
"It's just lack of football intelligence. Really poor mindset.
"I'm not so sure [if Fernandes' shot was going in], he's been given the goal. Poor defending from Phillips, he's got to move his feet a bit quicker."
