City manager Roberto Mancini expects neighbours Manchester United to be successful in all their matches between now and the end of the season.
And De Jong believes leaders City, who boast a slender two-point lead over their nearest rivals, cannot afford to drop another point as they look to secure a first top-flight title since 1967-68.
“From this stage every game is like a final,” said the Netherlands midfielder ahead of City’s tricky away game at Swansea on Sunday.
“That means we have to win every game. If United win every game, we can’t drop any points. It’s a challenge but without a challenge you’ll never win anything.”
City are looking to bounce back from Thursday’s round of 16 first leg 1-0 Europa League defeat to Sporting Lisbon in Portugal.
Although Swansea start the weekend 14th in the table, the Welsh club have won an army of new admirers since clinching promotion last May with their free-flowing passing game.
Mancini expects his team’s title credentials to be severely tested by Swansea, who have recorded some impressive results, including a 3-2 home win over Arsenal in January and a 1-1 draw against Chelsea.
“They are playing very well, they play good football,” said City’s Italian manager.
“They started the season very well and they have continued to play good football. I think it will be a tough game.”
Swansea manager Brendan Rodgers was recently mentioned as a potential Chelsea manager, and Mancini believes he has the ability to go far in the game.
“I think that he is a good manager,” added Mancini.
“It is clear it is totally different, playing for the title compared to avoiding relegation, but I think he has the capacity.”
City will definitely be without captain Vincent Kompany, who pulled up with a calf injury during the defeat in Portugal.
In addition, Pablo Zabaleta is also nursing a thigh problem while Mancini has doubts over defenders Joleon Lescott (groin) and Micah Richards (thigh).
Striker Carlos Tevez is still building up his match fitness.
Swansea are without Nathan Dyer, a key player for them this season, who starts a three-match ban.
Swansea’s Spanish right-back Angel Rangel has warned City that Swansea have come a long way since losing 4-0 to Mancini’s expensively-assembled side at the start of the season.
“We didn’t create too much that day, but we are more confident in our attacking play now,” said Rangel.
“Sunday will be interesting because we have been very strong at home and it’s a chance for us to show them how much we have matured in this league.
“Of course, they have top quality all over the pitch – and on the bench too. They probably have around £200 million of talent sitting on the bench every week, so they have plenty of options.
“The difference in these games is that you have to be clinical. You won’t get many chances, and if you get one then you have to take it.”