Ferguson regards his current squad as being better than the one which was dismantled by Barcelona in the 2011 Champions League final.
However, he recognises Wednesday's game at Real Madrid represents a significant challenge that has to be overcome.
"People say we are not as good as the teams of the past but sometimes people have foggy impressions, I do myself at times," he said.
"This team doesn't know when it is beaten. It has good individual players.
"But the acid test is tomorrow."