Manchester United's defense, according to former Liverpool defender Jamie Carragher, is a "joke" and a "mess" after the Red Devils were thrashed 5-0 by the Merseysiders on Sunday.
At Old Trafford, Liverpool scored their biggest ever away win over their historic rivals, with goals from Naby Keita and Diogo Jota giving them an early two-goal lead before Salah completed the onslaught with a hat-trick.
The Reds scored their fifth goal five minutes into the second half and had a numerical advantage for the final 30 minutes after Paul Pogba was shown a red card, but they failed to add to their lead, and Carragher believes they squandered a chance to heap more agony on Ole Gunnar Solskjaer's side.
"I'm not trying to be clever here, I don't think Liverpool were actually at their absolute best in terms of actual possession. But whenever they made passes and got in and around United's back four... that's just a joke of a back four at the moment. It was just a mess," Carragher told Sky Sports News.
"It'll never get better than that. If there was one slight disappointment it's that there was half an hour to go against United with 10 men - you'll never get that opportunity again.
"Manchester United and Liverpool are the biggest rivals, maybe in world football - two huge clubs, huge rivalry, and huge respect even for what they've achieved, but you're not going to get that opportunity too often."
The Reds are now second in the Premier League rankings, one point behind leaders Chelsea, while Manchester United sit seventh.