"Blackburn were magnificent. We were left trailing in their wake for so long that we just had to improve. The second half saw a transformed team," he admitted. "The most important thing was the substitution of Nicky Butt. He gave us a bit of steel and a bit of energy in midfield."
Ferguson added that Cole's equalising goal was the turning point after the pounds 7m striker cut in from the right and delivered a pinpoint drive across Rovers' keeper Alan Fettis into the far corner.
"He turned it round for us really. Once we got the equaliser then they knew we had come back from nothing. They had been giving us a `doing' and then suddenly they have let in a goal 10 minutes into the second half. That made a difference.
"All round I think you have to say it was a gritty performance and that we got out of jail."
Ferguson, whose side face Liverpool next at Old Trafford on Friday, warned his squad: "The first half was a reminder to us and if they don't take that on board, then they're not the players I think they are. The one thing you know in this League is that every team are fighting for their lives and there's a great animal quality about it. But we know after having this lesson tonight how tough it is going to be on Friday."
Roy Hodgson, the Blackburn manager, was encouraged by Ferguson's compliments, but was left frustrated by the result and admitted that his side's championship hopes were over.
"To be honest, we haven't had any serious ideas of reaching first or second place since we had a bad March, when we lost a lot of games and we should have done better," he said.
"The main point for us is to keep playing as well as we've done tonight and hope we get enough points to get us into the Uefa [Cup] because that was our aim at the beginning of the year."