City will equal Arsenal's Premier League record of 14 consecutive wins with victory Old Trafford on Sunday, but head into the game on the back of a 2-1 defeat to Shakhtar Donetsk in the Champions League, their first since April.
United's 2-1 win over CSKA Moscow on Tuesday levelled a club a record of 40 games without loss at Old Trafford and De Gea believes his side can continue their impressive run on Sunday.
De Gea, speaking exclusively to Sky Sports pundit Thierry Henry on Nissan Match Zone, said: "Can City stop United? We play at home with the fans.
"It's a derby, we have confidence, we feel really strong and we want to win.
"The team is in a good moment, we won two difficult away games so we have confidence and we know we play an important game. We really want to win."