Two poor results, the one at Wigan and the City game means that United now need help from the two final teams to play City this season to stand any chance of retaining the Premier league title.
De Gea is hopeful that Newcastle can get a result against City on their own patch this afternoon as the Toon Army go all out to bring Champions League football to the Geordie population for next season.
The United keeper told the Sun: "There have been lots of ups and downs in the title race. But we have thrown away our advantage in games against Wigan and Everton.
"We only have ourselves to blame. There are two games left for both of us and they will be equally tough.
"Our objective is to take maximum points and hope that City slip up. I saw Newcastle against Chelsea and they could play a vital part in the title race, they could hold the key to United retaining the title.
"It won’t be easy for City and we just have to hope they fail to win and we get back to winning ways against Swansea."
De Gea admitted the recent derby defeat was hard to take and is desperate for the Red Devils to regain top spot come season’s end.
"It has proved to be an expensive and painful defeat,"he added.
"There is no doubt that finishing second would be no consolation. It would be a huge disappointment for everyone at the club."