Ferguson made 10 changes to the line-up that started the 3-3 draw at Everton on Saturday.
"The criticism will be why I didn't play a stronger team," he said. "I think I played a very strong team. People forget eight of them played against Chelsea in the Charity (Community) Shield.
"It's a terrific squad of players we have and there was no problem playing them.
"They should have won that game, but give credit to Rangers, their system is very difficult to break down."
Ferguson added: "I think we played with great intensity and good commitment. But Rangers just went back to the penalty box and it was successful.
"We said they had two draws away from home and lost 1-0 in Seville last season so they have a successful format."