The Dutch, who like the Chileans won their first two games, only need a draw because their goal difference is much better. (Agencies)
Chile beat Australia 3-1 and stunned world champions Spain 2-0. "They looked very good. They looked fit, they look strong, they play together," Van Persie told a news conference.
"I think that four or five players made Spain's life very hard. So we've got a big task. It will be very hard to at least draw against them," he said.
If the Dutch win their group they will meet the runners-up in Group A, which looks like being either Mexico or Croatia. If they come second, they could well end up playing Brazil.
"We want to secure first place and then we'll see what happens," said the 30-year-old Van Persie.
Van Persie, suspended for the Chile game after picking up two yellow cards in the first two matches, brushed off talk about becoming the top scorer at the tournament.
"The main thing is to qualify for the next round, and the round after, and the round after that and do well as a country," he said.
Van Persie said his Manchester United team mate Wayne Rooney had been unlucky to be on the losing side when England crashed out of the World Cup after a 2-1 defeat by Uruguay on Thursday.
"I think it's a shame because in my opinion England played quite well. They had their moments ... Rooney could have scored four goals," he said.
"I don't think it's him to blame, for example, he's under massive pressure and in my opinion he did very well ... but that's that thin line between winning or losing, going through or going home," he said.
The Dutch, who like the Chileans won their first two games, only need a draw because their goal difference is much better.