Ferdinand walked into the boozer after the lunchtime loss to the Gunners.
He said: "When you lose against Arsenal it does your head in. I was going back to meet my family in a hotel for my birthday.
"It was meant to be a happy time. So I thought before I go back maybe I'll go and have a couple of drinks in a pub.
"I told the driver to stop off at some pub. He said 'I can't let you go in there.' I had my United tracksuit on in a West Ham area.
"I said 'Nah, just drop me off.' So he did. I could see people going 'What's he doing in here?'
"I had a couple of drinks, three packets of crisps and sat in the corner watching the results on TV. Players do do normal things."