The Azzurri midfielder has expressed caution over his country's clash with the Central American side following their shock victory over Uruguay last week
The Roma midfielder helped the Italians get off to a winning start against England in Group D but they now face a dangerous Costa Rica outfit who also took maximum points in their opener.
The Central American side came from a goal down to shock Uruguay 3-1 last week and De Rossi is keen to ensure Italy treat Jorge Luis Pinto’s side with respect as they look to all but confirm their own last-16 spot.
"We should fear them a bit. You need a healthy fear against a team that surprised everyone with their victory over Uruguay," he said.
"Nobody thought they would get such a clear result against a very strong side.
"They'll be fired up after that win. If they had lost 4-0 then we could've underestimated them, but in this case we cannot possibly do that.
"I hope, and am convinced, that we can virtually secure qualification by beating Costa Rica. A victory would put a strong stamp on our ticket to the next round."
Italy are hoping to welcome back captain Gianluigi Buffon from injury for the match, while De Rossi himself should be fully fit after sitting out of training with a neck problem.