The 26-year-old Roma midfielder was speaking ahead of this weekend's match against New Zealand.
“We are always improving, from Sestriere to today, getting through Mexico, Switzerland and Paraguay. We'll keep on growing,” De Rossi explained.
When asked for his assessment of New Zealand, he said: “In terms of quality we are superior. We must beat them despite the difficulty that they will present us with.
“We mustn't change our shape on the basis of New Zealand's qualities. There are no longer games in the World Cup, which finish 5-0 or 6-0.
“If we were to lose it would be as if the New Zealand rugby team had been knocked out. That would be the scale of it. It would be a failure not to qualify from the group and also for the quarter-finals. Finishing in the top four would instead be an important achievement.
“We must focus on finishing in the top four. Then, if we meet Spain it will become a little final. We played a good game against Paraguay. Perhaps we weren't stinging enough. We were lacking something in the final pass.
“We'll try to do more up front. We lacked a little ruthlessness and lucidity, but also in 2006 the goals eventually started to come."