De Gea ended up being named in the PFA Premier League Team of the Year last term so impressive did his contribution to United's 20th league title eventually become.
He has maintained that form this season and is now firmly established as the Red Devils' main man between the sticks.
It has not always been that way.
There was a period last season when Sir Alex Ferguson seemed undecided about picking De Gea or deputy Anders Lindegaard, whilst his debut campaign the year before highlighted physical weaknesses that can be easily exploited in England's top flight.
Yet De Gea believed the snipers were being harsh in the extreme as he struggled to get used to life the toughest of environments.
"If I am honest, yes (the criticism was unfair)," De Gea told Inside United.
"I was very young and I had arrived at a new club from another country.
"I was learning a whole new language, I was adapting to a new style of football and new team-mates.
"That's a lot to take in and it's natural that it will take a little bit of time to settle.
"It wasn't easy hearing this criticism but I tried to use it to motivate me and make me stronger.
"I think I have improved as a goalkeeper because of it, actually.
"I like to think that from bad things you can derive good results."
Having stabilised their season with a nine-match unbeaten run in all competitions prior to the international break, United will be looking to maintain the momentum at Cardiff on Sunday.
However, the excitement Ryan Giggs might feel at the chance of representing United in his home town for the first time will be tempered by the fitness concerns around the Red Devils' camp.
With Michael Carrick and Phil Jones ruled out by Achilles and groin injuries respectively and £27.5million new-boy Marouane Fellaini still handicapped by the wrist problem that will eventually require surgery, manager David Moyes does not have extensive options in central midfield.
In addition to Giggs, Tom Cleverley offers another option, as does Anderson, who has not featured in a league game for almost two months since the Old Trafford defeat by West Brom.
Further forward there are doubts over Danny Welbeck and Robin van Persie, who both missed the recent international double-headers.