Salah is set to pose the greatest attacking threat to City, having already scored 37 goals in all competitions this season, and Van Dijk believes the Egypt worldwide is nearly unstoppable when at his best.
The former Barcelona coach also revealed that he hopes his team do not become too affected by what is sure to be an unbelievable atmosphere at Anfield when the two sides face each other on Wednesday.
"Not just [Salah], Mane and Firmino, all three, they are nearly unstoppable".
"With the distance we have, we have to be focused on the Champions League and in the middle we have United - who of course we are going to try and beat and try and play - but the line-up will be thinking about Liverpool".
McMahon thinks the tie could be decided on away goals and has urged Liverpool to make sure they do not concede in the first leg, with even 0-0 being a good result.
"Yeah, I'll have to do that [make special provisions for Salah]", Guardiola told reporters.
City boss Pep Guardiola conceded that stopping the dynamite trio will be a almost impossible task, noting that the Reds have goals in them all over the pitch.
The suggestion from Guardiola was that he may rest some players for the derby ahead of the second leg against Juergen Klopp's side at the Etihad three days later. You could see in their faces in the first half that they didn't know what was happening. I hope he can help us.
Oh, how the tables have turned on one Mr. Jose Mourinho, who just last month said something nearly identical about Liverpool, Man United's other bitter rivals. It is 180 minutes.
"You have to use all the squad but that doesn't mean the guys who play are not going to prepare to win".