"I think it was really important that we got into it quickly and we have done that – four games gone and we are more than happy with it."
Sir Alex had admitted that early qualification would allow him some much-needed squad rotation in the final group games against Galatasaray and Cluj, but Phelan insists United will still respect the ramifications of those games for the remaining three sides in Group H.
"It does now give us that opportunity to have a look at a couple of other players on this stage, and I am sure we will do that," he said, "but we have to give credit to the competition as well.
"And as Manchester United we will do that. But it was important we got the job done as quickly as possible, in order for us to concentrate on the Premier League."