"It's an opportunity to keep the players' engines running," Fergie told press reporters on Friday.
"They have all been applying themselves very well, so rotating the squad has been working well. It certainly helps us to be able to make changes.
"We played on a tiring pitch at Wembley, then we had to travel back home and up to the north-east, which itself can be exhausting.
"But there's no doubt the changes helped and against Fulham hopefully they'll help again."