For the umpteenth time during Ferguson's legendary reign, United looked dead and buried with time running out of a game they could ill afford to lose.
But in a sensational 19 minutes that included a 14-minute Wayne Rooney hat-trick, the leaders turned a 2-0 defeat into a 4-2 victory, propelling them eight points clear at the top of the table and piling the pressure back on Arsenal and Chelsea behind them.
"We played like champions," said a delighted Ferguson.
"It was a real championship performance as far as I'm concerned.
"I said to them at half-time, 'Look, goal difference doesn't matter now - you're getting something from this game'.
"'The next goal wins the game'.
"That's why I put Ryan (Giggs) back to left-back to have a go and just attack.
"It paid dividends and I'm pleased with that."
So often have United produced such remarkable fightbacks, it is no longer a surprise when they pull one off.
Ferguson added: "They've got the ability to turn it around - that's the first thing.
"But they've got great faith in themselves, faith in the team, faith in their team-mates.
"It doesn't always work but you can rest assured, they keep trying to create and play their football, and in the second half we dominated."
In truth, United dominated almost from start to finish and only found themselves 2-0 behind after Patrice Evra and Nemanja Vidic inexplicably conceded penalties.
The Scot could not resist questioning West Ham's second penalty today, with the offence arguably taking place outside the box.
"Bit fortunate," said Ferguson, who insisted his side fully merited their win.
He was also delighted with Rooney's first hat-trick of what has been a turbulent season for the England striker.
"Marvellous," he said.
"I hope there's another couple."
Ferguson, who confirmed goalkeeper Edwin van der Sar was not risked due to a groin injury ahead of Wednesday's Champions League clash with Chelsea, felt today's win would hit United's title rivals hard.
He added: "It makes an impact on us.
"Seven games left.
"You can count the games down one by one.
"It ends up you run out of games and hopefully we're there.
"Arsenal have games in hand and it could go to goal difference but I somehow don't think so."