De Gea has struggled to fill the boots of Van der Sar since the Dutchman retired at the end of last season, making a number of high-profile blunders that saw him dropped from the side. The £18million man was recalled for Sunday's game at Chelsea, producing a Jekyll-and-Hyde display that saw him flap at more than one cross but also make a stunning late save.
Van der Sar said: "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."
De Gea had lost his place to Anders Lindegaard, who impressed in goal before picking up an injury that has ruled him out for a month.
Van der Sar said: "I spoke to Anders and he's disappointed of course, that he's injured at the moment because he's really been magnificent."
Sir Alex Ferguson could have been forgiven for sending out an SOS to Van der Sar, who admitted he was missing the game. But Van der Sar insisted he was not about to follow in the footsteps of Paul Scholes, who came out of retirement last month.
"I got a few text messages from friends saying, 'What about you?'," Van der Sar said. "I'm quite happy at the moment. There's no doubt in my mind."
Van der Sar, 41, was not surprised at Scholes' u-turn, having spoken to the midfielder last year.
He said: "I was at Carrington and he was watching a training session and I said, 'So, how do you like it?'.
"He said, 'Not really. I miss it'. He was still there doing his work as an assistant coach with the reserve team so it was probably a little bit easier to get back in."
Source: PA
Source: PA