Despite surrendering a lead to lose 2-1 at Everton, City can still secure a Champions League spot and win their first trophy in 35 years in the next six days. Roberto Mancini's men face Tottenham, their chief rivals for fourth spot in the Barclays Premier League, on Tuesday and then tackle Stoke in the FA Cup final.
Beating Spurs would guarantee a qualifying place in Europe's elite competition and put the club in good heart for Wembley but De Jong feels the team must learn from their Goodison Park reverse, saying: "Nobody likes to lose a game, especially a game like this - it was an unnecessary loss."
He added: "We dominated the first half but didn't create that second goal.
"We knew it was going to be a hard afternoon with the crowd behind them, so we just have to learn from this one and focus on the other games.
"It is a very important week for the club, for the fans and all the squad as well.
"It is do or die at the moment for Manchester City.
"Fourth place is in reach. We just have to win the game and then the next game (after that) is going to mean everything as well - we have the chance to win the FA Cup after 35 years.
"It is going to be a big week and we all have to be positive."
Source: PA
Source: PA