Alejandro Sabella's Argentina have been criticised for being too reliant on Messi, who has four man-of-the-match awards through as many games in Brazil.
The South Americans face Belgium in the quarter-finals at the Estadio Nacional Mane Garrincha in Brasilia on Saturday.
Hazard said keeping Messi quiet would go a long way towards helping Belgium into the last four.
"We know the best player in the world is in this team, but we are not afraid," he told reporters.
"We can win. Argentina have done well, but they have one big player who can make the difference every game. If we can stop him, we have a chance, but it will not be easy.
"For me, he is the best in the world. I don't know how we can stop him, but we will watch videos and we will try to win.
"They have Angel di Maria as well, but Messi is the difference."
Hazard hopes his team can match or better the efforts of the 1986 Belgium team, who suffered a loss in the third-place play-off.
"We have four victories in four World Cup games and there are not many teams who have managed this. Now we have to keep it going," the Chelsea star said.
"Matching the team of 1986 is an objective. It's not impossible and is there to fight for. We have to win the match with Argentina."
