United won the match 1-0 after a penalty goal from winger Cristiano Ronaldo.
Ferguson said: “What you saw today was human courage.
“The players showed great courage to come back from Wednesday and we are happy with 1-0, I think.
“It wasn’t a great performance but derby games are like that and in the end we got through it.”
United will be crowned champions if Chelsea slip up against Arsenal on Sunday, but Ferguson will not watch the game.
He said: “A draw would do us fine.
“And if we have to go to Chelsea on Wednesday to get a result to win the title I would look forward to it.
“I won’t be watching Chelsea’s game – if the weather is nice I might go and have a round of golf.”