The Belgians are considered a good outside bet to lift the World Cup for the first time and start the tournament on Monday against rank outsiders Panama in Group G.
Courtois said his Chelsea team mate Hazard, who scored the winning goal in the FA Cup final last month, was highly motivated.
"I don't think I've ever seen him train or play as amazing as in the last three games," Courtois told reporters. "I think he has reached another level of his game."
Courtois, however, was quick to stress that no one player is going to win the World Cup and played up the new sense of spirit in a team built from what is known as Belgium's Golden Generation.
"I don't think it is only Eden we need at his best," the Chelsea keeper added. "I think we need Romelu (Lukaku) to score goals, for Kevin (De Bruyne) to play like at (Manchester) City. I think if you want to go far you need your players to be at their best."
"I think we have the quality, we have the talent and we know each other very well. Most of us are in peak form of our football life, we feel confident. I think we are outsiders to win but we have a chance to go far and as a team we believe. We don't want to say we will win but we have the quality to."
Coach Roberto Martinez warned fans not to expect an easy ride against Panama, even though they have scored just one goal in their last six games.
"Panama are one of the stories of the World Cup, they are arriving for the first time against the odds and that is very dangerous," Martinez said. "They have a belief and competitive nature.
"It is their first game and will be their first game forever and my worry is that we don't get affected by that. This is a game where we cannot get frustrated, we cannot expect to win quickly."
(Reporting by Andrew Downie, editing by Ed Osmond)
