Allardyce was axed by Blackburn’s new owners, the Venky’s Group, on Monday.
The United boss told Sky Sports: “He phoned me at 3.10pm today saying ‘can I have a cup of tea tonight?’ because he was coming to the game. Then he phones me at half past four and says ‘I’ve been sacked’.
“I’ve never heard of such a stupid decision in all my life, it’s absolutely ridiculous. I don’t know what they’re doing up there, but deary me.
“It confounds common sense to be honest with you. Absolutely ridiculous.
“I wouldn’t like to follow him!”