De Gea, who left Atletico Madrid to succeed Edwin Van der Sar at United in the summer, made a few high-profile but ultimately uncostly errors during his first few games at Old Trafford and has taken time to settle at his new club.
The 20-year-old Spaniard was rested for United's Champions League match against Benfica in midweek and Ferguson gave a spikey response when asked about the excellent performance of stand-in goalkeeper Anders Lindegaard after the 1-1 draw at the Estadio de Luz.
And now the United manager has spoken about the pressure being heaped on his new signing. "There is obviously an agenda on De Gea and we experienced that again on Wednesday," said Ferguson. "It seems to me people are desperate for the boy to fail. That's the impression I get and I don't understand it.
"De Gea hasn't been flapping about in the goalmouth, he has been really composed. He's outstanding," Ferguson told the Mail on Sunday.
"Both our goalkeepers can use the ball, which is a fantastic asset in the modern game. At Bolton last weekend, he [De Gea] started seven attacks. He chipped the ball out and the attacks ended up in their penalty area. I think he had a 90% pass completion."
Ferguson has confirmed that De Gea will be restored to the starting line-up for Sunday's match with title-rivals Chelsea as he continues to put his faith in the young goalkeeper.
It had been speculated that De Gea would be dropped for the game at Bolton on September 10 as he would have to withstand an aerial assault but Ferguson said: "Those reports didn't bother him - I'd told him on the Thursday he would be playing.
"There's a lot that he has had to deal with and he's showing a lot of composure. He is 20 and coming into a country where he doesn't know the culture. He doesn't speak English, he's been looking for a house and he's found one now; he's been learning to drive in England."
Ferguson also had some words for comfort for Lindegaard, who will be back on the bench for the Chelsea match.
"Anders showed in Lisbon that he is a bloody good goalkeeper but David plays on Sunday. That was always the arrangement."
"We've got two terrific goalkeepers. Anders has done well and been patient. He knew we would be signing another keeper. He's happy to be at United and in a position to challenge for a place."
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