The United stopper has been in fine form at Old Trafford this term under Louis van Gaal and has been linked with a move to Real Madrid.
He moved to United in 2011, leaving Atletico, but is desperate to return to the elite level of the Champions League.
"We have to qualify for the Champions League no matter what," De Gea told Manchester United's official website.
"We already missed out last season, and a team like Manchester United cannot do that two years in a row."
De Gea, though, admits he's learnt a lot in England and has developed alongside Victor Valdes.
Valdes was signed in January after his contract at Barcelona had expired.
And the addition of the Spain keeper did little to stop suggestions De Gea would return to La Liga.
"Truth be told, English football has changed me a great deal," he added.
"I’ve developed a lot physically, greatly improved my concentration and generally improved all aspects of my game.
"I was very young when I came here, but four years on, things are very good overall. This league really suits me, as you learn a lot here.
"I’m a composed, calm type, which helps me in my profession. As a keeper, you need to convey a sense of calm to the rest of the team."