De Gea was earmarked by manager Sir Alex Ferguson as the veteran Dutchman's successor when he retired last summer, securing De Gea's signature from Atletico Madrid and handing him the number one shirt.
However the Spanish keeper has struggled to live up to his billing so far this season, producing a number of nervous displays that saw him replaced by rival shot-stopper Anders Lindegaard.
The Dane recently suffered an injury in training, meaning De Gea was restored to the starting line-up for Sunday's thrilling 3-3 draw with Chelsea, where he pulled off a sprawling save in the dying minutes to keep out Juan Mata's free-kick.
"It's always difficult if you're coming into a new club and new league, especially the English one. It's a very demanding one, can be a very tough one. He has to deal with that. They paid a lot of money for him and he has to come through that," he said, as reported by The Guardian.
"I spoke to Anders and he's disappointed of course, that he's injured at the moment because he's really been magnificent."
"I got a few text messages from friends saying: 'What about you?'," he said. "I'm quite happy at the moment. There's no doubt in my mind."
