The world number one ODI batsman expects a competitive tournament where even the top sides won't be able to take things easy in any matches.
"I was pretty happy with our preparations for the Champions Trophy, although obviously you don't want to lose a series that you play in," said De Villiers at the pre-tournament dinner.
"But I know that we finished on a high, and there were encouraging signs throughout the series and those are the kind of things we like to focus on.
"We're still ranked the No 1 team in the world going into the tournament, so there are quite a few reasons for us to be confident, but we're still humbled at the same time and know that we have to work hard and take it one step at a time to win this.
"Anything can happen on the day in one-day cricket, that's a fact, and especially with a tournament like the ICC Champions Trophy.
"When the world's top eight teams are competing for one trophy, it's going to be very competitive. I'm sure there will be some close games, and I guess whichever team takes their opportunities the most will come out on top.
"We know we're still going to have to play well, and imitate what we have been doing over the last 18 months, but we are ready for that. We are very well prepared and ready to move forward."
De Villiers insists the Proteas will look to hit the ground running, avoiding a repeat of their start to the England series where his team lacked sharpness in the field in the opener in Leeds.
"It's vital that we get off to a good start," said De Villiers.
"There is not a lot of time in this tournament to bounce back, it's very short with only a few games before the knockout.
"I think we can expect to see more of what we have been seeing over the last year from South Africa in this tournament - a brave brand of cricket.
"That is what I believe we have been playing, and it has been working for us. We've got a really good side, and I have full trust in the guys to come out and play really well.
"We're going to take it one step at a time. So many guys have said that before and it’s a bit of a cliché, but it's important in these kind of tournaments not to look too far ahead.
"This tournament happens at a rapid pace and there is no room for error, so if you look too far ahead, you might stumble over an obstacle or two."
The Proteas get their Champions Trophy underway against Sri Lanka on Saturday (11:30 SA time).