The Reds may have beaten the Magpies at Old Trafford last week in the Capital One Cup but a visit to the passionately partisan Sports Direct Arena for Barclays Premier League action will prove a much tougher test.
The boss should know. After all, United lost 3-0 there in January to register a second straight loss following a surprise home defeat against Blackburn Rovers on New Year's Eve.
"It's always a difficult place to go," Sir Alex said. "They'll be buoyed by their support. I think Alan Pardew has a really good team there. After the game against Tottenham we have to make sure we don't lose.
"We played some really good football at times [against Tottenham] and it was interesting to play Rooney, Chicharito and Robin van Persie together. It gives me some thoughts and options for certain games."
Newcastle are in fine form at the moment (just one defeat – against United – in the last eight
"Demba Ba and Papiss Cisse both have good scoring records. They rested Ba last night and played Shola Ameobi. I'm not sure what combination it will be on Sunday."
- Sir Alex Ferguson